{"items":[{"id":"NVI-00005147","kind":"vulnerability","title":"ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay","revision":3,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected.","NVD lastModified does not establish freshness of every associated CPE record."],"lifecycle":"active","identifiers":["GHSA-6gvq-jcmp-8959","CVE-2025-68113"],"plain_summary":"OSV carries this publisher advisory for altcha-lib, altcha-org/altcha, github.com/altcha-org/altcha-lib-go, org.altcha:altcha, altcha. This is an aggregated source copy; consult the original publisher and compare update dates.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"The original advisory lists fixed boundaries 1.4.1 for altcha-lib. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null},{"summary":"The original advisory lists fixed boundaries 1.3.1 for altcha-org/altcha. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null},{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-7d2881d14c93ca08565897b8c4805ef6"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-07T19:10:00.160Z","value":"6.5 MEDIUM (3.1)","meaning":"security-advisories@github.com severity; no combined Null risk score.","source_id":"sr-4802cb536ad87139611681bb69de5ee5"},{"kind":"EPSS","as_of":"2026-10-31T12:00:27.000Z","value":"0.463%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.40116. Missing scores are unknown.","source_id":"sr-7d2881d14c93ca08565897b8c4805ef6"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-8428a7ebaf34249bd25ce259e897b021","url":"https://github.com/advisories/GHSA-6gvq-jcmp-8959","basis":"vendor_advisory","notes":"GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.","title":"GHSA-6gvq-jcmp-8959","publisher":"GitHub Advisory Database via OSV","observed_at":"2026-10-31T21:41:59.936Z"},{"id":"sr-4802cb536ad87139611681bb69de5ee5","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68113","basis":"official_catalog","notes":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","title":"CVE-2025-68113","publisher":"NIST National Vulnerability Database","observed_at":"2026-11-01T01:40:29.811Z"},{"id":"sr-7d2881d14c93ca08565897b8c4805ef6","url":"https://www.first.org/epss/data.html","basis":"official_catalog","notes":"FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.","title":"CVE-2025-68113","publisher":"FIRST EPSS","observed_at":"2026-10-31T22:06:15.373Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-lib","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.4.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-org/altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"github.com/altcha-org/altcha-lib-go","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"org.altcha:altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]}],"null_published_at":"2026-11-01T19:14:01.619Z","source_updated_at":"2026-09-10T03:50:31.591Z","source_disclosed_at":"2025-12-16T00:43:52.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.","null_first_observed_at":"2026-10-31T21:41:59.936Z"},{"id":"NVI-00005147","kind":"vulnerability","title":"ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected.","NVD lastModified does not establish freshness of every associated CPE record."],"lifecycle":"active","identifiers":["GHSA-6gvq-jcmp-8959","CVE-2025-68113"],"plain_summary":"OSV carries this publisher advisory for altcha-lib, altcha-org/altcha, github.com/altcha-org/altcha-lib-go, org.altcha:altcha, altcha. This is an aggregated source copy; consult the original publisher and compare update dates.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"The original advisory lists fixed boundaries 1.4.1 for altcha-lib. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null},{"summary":"The original advisory lists fixed boundaries 1.3.1 for altcha-org/altcha. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null},{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-4802cb536ad87139611681bb69de5ee5"],"action_type":"investigate","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[{"kind":"CVSS","as_of":"2026-10-07T19:10:00.160Z","value":"6.5 MEDIUM (3.1)","meaning":"security-advisories@github.com severity; no combined Null risk score.","source_id":"sr-4802cb536ad87139611681bb69de5ee5"}],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-8428a7ebaf34249bd25ce259e897b021","url":"https://github.com/advisories/GHSA-6gvq-jcmp-8959","basis":"vendor_advisory","notes":"GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.","title":"GHSA-6gvq-jcmp-8959","publisher":"GitHub Advisory Database via OSV","observed_at":"2026-10-31T21:41:59.936Z"},{"id":"sr-4802cb536ad87139611681bb69de5ee5","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-68113","basis":"official_catalog","notes":"This product uses data from the NVD API but is not endorsed or certified by the NVD.","title":"CVE-2025-68113","publisher":"NIST National Vulnerability Database","observed_at":"2026-11-01T01:40:29.811Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-lib","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.4.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-org/altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"github.com/altcha-org/altcha-lib-go","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"org.altcha:altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]}],"null_published_at":"2026-11-01T14:34:07.643Z","source_updated_at":"2026-09-10T03:50:31.591Z","source_disclosed_at":"2025-12-16T00:43:52.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"Source facts changed; compare the preserved prior revision.","null_first_observed_at":"2026-10-31T21:41:59.936Z"},{"id":"NVI-00005147","kind":"vulnerability","title":"ALTCHA Proof-of-Work Vulnerable to Challenge Splicing and Replay","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-6gvq-jcmp-8959","CVE-2025-68113"],"plain_summary":"OSV carries this publisher advisory for altcha-lib, altcha-org/altcha, github.com/altcha-org/altcha-lib-go, org.altcha:altcha, altcha. This is an aggregated source copy; consult the original publisher and compare update dates.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"The original advisory lists fixed boundaries 1.4.1 for altcha-lib. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null},{"summary":"The original advisory lists fixed boundaries 1.3.1 for altcha-org/altcha. Confirm the publisher’s latest guidance.","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"action_type":"vendor_patch","limitations":"Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system.","current_supported_target":null}],"schema_version":"1.1.0","source_metrics":[],"why_it_matters":"Published affected context helps an owner decide what evidence to gather. This report has not examined your application.","related_sources":[{"id":"sr-8428a7ebaf34249bd25ce259e897b021","url":"https://github.com/advisories/GHSA-6gvq-jcmp-8959","basis":"vendor_advisory","notes":"GitHub-origin advisory, CC-BY-4.0; OSV is an aggregate copy, not independent corroboration.","title":"GHSA-6gvq-jcmp-8959","publisher":"GitHub Advisory Database via OSV","observed_at":"2026-10-31T21:41:59.936Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-lib","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.4.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha-org/altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.1"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"github.com/altcha-org/altcha-lib-go","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"org.altcha:altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.3.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["ECOSYSTEM: introduced 0; fixed 1.0.0"]},{"certainty":"source_listed","source_ids":["sr-8428a7ebaf34249bd25ce259e897b021"],"technology":"altcha","known_exclusions":[],"conditions_summary":"### Impact\n\nA cryptographic semantic binding flaw in ALTCHA libraries allows challenge payload splicing, which may enable replay attacks. The HMAC signature does not unambiguously bind challenge parameters to the nonce, allowing an attacker to reinterpret a valid proof-of-work submission with a modified expiration value. This may allow previously solved challenges to be reused beyond their intended lifetime, depending on server-side replay handling and deployment assumptions.\n\nThe vulnerability primarily impacts abuse-prevention mechanisms such as rate limiting and bot mitigation. It does not directly affect data confidentiality or integrity. \n\n### Patches\n\nThis issue has been addressed by enforcing explicit semantic separation between challenge parameters and the nonce during HMAC computation.\n\nUsers are advised to upgrade to patched versions.\n\n### Workarounds\n\nAs a mitigation, implementations may append a delimiter to the end of the `salt` value prior to HMAC computation (for example, `?expires=&`). This prevents ambiguity between parameters and the nonce and is backward-compatible with existing implementations, as the delimiter is treated as a standard URL parameter ","public_affected_ranges":["SEMVER: introduced 0; fixed 1.0.0"]}],"null_published_at":"2026-10-31T22:13:01.451Z","source_updated_at":"2026-09-10T03:50:31.591Z","source_disclosed_at":"2025-12-16T00:43:52.000Z","is_synthetic_fixture":false,"null_last_reviewed_at":null,"public_change_summary":"First indexed by Null; source disclosure date is shown separately.","null_first_observed_at":"2026-10-31T21:41:59.936Z"}],"next_cursor":null,"snapshot_revision":"42594"}