{"items":[{"id":"NVI-00009137","kind":"vulnerability","title":"Authlib: Default JWT bearer grant accepts assertions for the wrong audience","revision":3,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fch4-3c6x-j4gc","CVE-2026-114618"],"plain_summary":"GitHub lists this reviewed advisory for authlib. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-0b42d44911def2abb8b4d367e779d1d0"],"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":"2026-10-27T15:39:10.000Z","value":"6.8 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-c3ac1d9d91b111c2bd6b3023b8d1541b"},{"kind":"EPSS","as_of":"2026-11-03T12:00:27.000Z","value":"0.351%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.28816. Missing scores are unknown.","source_id":"sr-0b42d44911def2abb8b4d367e779d1d0"}],"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-c3ac1d9d91b111c2bd6b3023b8d1541b","url":"https://github.com/advisories/GHSA-fch4-3c6x-j4gc","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fch4-3c6x-j4gc","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:56:51.534Z"},{"id":"sr-0b42d44911def2abb8b4d367e779d1d0","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-2026-114618","publisher":"FIRST EPSS","observed_at":"2026-11-03T17:44:07.776Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-c3ac1d9d91b111c2bd6b3023b8d1541b"],"technology":"authlib","known_exclusions":[],"conditions_summary":"## Description\n\n### Summary\n\nAuthlib's default RFC 7523 JWT bearer grant leaves `get_audiences()` empty, so `verify_claims()` only checks that an `aud` claim *exists* instead of requiring it to match the current authorization server's token endpoint. An attacker holding a legitimately issued JWT assertion for *any* audience can present it to a different authorization server sharing the same signing key and obtain an access token.\n\nTo be completely transparent, AI tools helped surface it. However, we have independently reproduced and carefully validated the issue. We follow responsible disclosure practices and are sharing this privately.\n\n### Affected Entrypoints\n\n- `authlib.oauth2.rfc7523.JWTBearerGrant` — default `get_audiences()` returns empty list\n- `authlib.jose.jwt.decode()` with `claims_options` for audience validation\n- `authlib.integrations.flask_oauth2.ResourceProtector.validate_request()` when audience checking is enabled\n\n### Exploit Path\n\n```\n1. Attacker authenticates to Service A (low-privilege)\n2. Authorization server issues JWT with \"aud\": \"https://evil.test/token\"\n3. Attacker presents this assertion to Service B's token endpoint\n4. Service B uses default JWTBearerGr","public_affected_ranges":["< 1.9.0"]}],"null_published_at":"2026-11-04T10:04:41.583Z","source_updated_at":"2026-10-27T15:39:10.000Z","source_disclosed_at":"2026-10-27T15:39:08.000Z","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":"2026-10-31T21:56:51.534Z"},{"id":"NVI-00009137","kind":"vulnerability","title":"Authlib: Default JWT bearer grant accepts assertions for the wrong audience","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fch4-3c6x-j4gc","CVE-2026-114618"],"plain_summary":"GitHub lists this reviewed advisory for authlib. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-90206f67ed6f61c6176956aab9e6e3de"],"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":"2026-10-27T15:39:10.000Z","value":"6.8 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-c3ac1d9d91b111c2bd6b3023b8d1541b"},{"kind":"EPSS","as_of":"2026-10-31T12:00:27.000Z","value":"0.351%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.28785. Missing scores are unknown.","source_id":"sr-90206f67ed6f61c6176956aab9e6e3de"}],"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-c3ac1d9d91b111c2bd6b3023b8d1541b","url":"https://github.com/advisories/GHSA-fch4-3c6x-j4gc","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fch4-3c6x-j4gc","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:56:51.534Z"},{"id":"sr-90206f67ed6f61c6176956aab9e6e3de","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-2026-114618","publisher":"FIRST EPSS","observed_at":"2026-10-31T22:06:15.374Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-c3ac1d9d91b111c2bd6b3023b8d1541b"],"technology":"authlib","known_exclusions":[],"conditions_summary":"## Description\n\n### Summary\n\nAuthlib's default RFC 7523 JWT bearer grant leaves `get_audiences()` empty, so `verify_claims()` only checks that an `aud` claim *exists* instead of requiring it to match the current authorization server's token endpoint. An attacker holding a legitimately issued JWT assertion for *any* audience can present it to a different authorization server sharing the same signing key and obtain an access token.\n\nTo be completely transparent, AI tools helped surface it. However, we have independently reproduced and carefully validated the issue. We follow responsible disclosure practices and are sharing this privately.\n\n### Affected Entrypoints\n\n- `authlib.oauth2.rfc7523.JWTBearerGrant` — default `get_audiences()` returns empty list\n- `authlib.jose.jwt.decode()` with `claims_options` for audience validation\n- `authlib.integrations.flask_oauth2.ResourceProtector.validate_request()` when audience checking is enabled\n\n### Exploit Path\n\n```\n1. Attacker authenticates to Service A (low-privilege)\n2. Authorization server issues JWT with \"aud\": \"https://evil.test/token\"\n3. Attacker presents this assertion to Service B's token endpoint\n4. Service B uses default JWTBearerGr","public_affected_ranges":["< 1.9.0"]}],"null_published_at":"2026-11-03T02:33:09.147Z","source_updated_at":"2026-10-27T15:39:10.000Z","source_disclosed_at":"2026-10-27T15:39:08.000Z","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":"2026-10-31T21:56:51.534Z"},{"id":"NVI-00009137","kind":"vulnerability","title":"Authlib: Default JWT bearer grant accepts assertions for the wrong audience","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-fch4-3c6x-j4gc","CVE-2026-114618"],"plain_summary":"GitHub lists this reviewed advisory for authlib. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.","review_status":"source_listed","control_topics":[],"public_actions":[{"summary":"Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.","source_ids":["sr-c3ac1d9d91b111c2bd6b3023b8d1541b"],"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":"2026-10-27T15:39:10.000Z","value":"6.8 medium","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-c3ac1d9d91b111c2bd6b3023b8d1541b"}],"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-c3ac1d9d91b111c2bd6b3023b8d1541b","url":"https://github.com/advisories/GHSA-fch4-3c6x-j4gc","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-fch4-3c6x-j4gc","publisher":"GitHub Advisory Database","observed_at":"2026-10-31T21:56:51.534Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-c3ac1d9d91b111c2bd6b3023b8d1541b"],"technology":"authlib","known_exclusions":[],"conditions_summary":"## Description\n\n### Summary\n\nAuthlib's default RFC 7523 JWT bearer grant leaves `get_audiences()` empty, so `verify_claims()` only checks that an `aud` claim *exists* instead of requiring it to match the current authorization server's token endpoint. An attacker holding a legitimately issued JWT assertion for *any* audience can present it to a different authorization server sharing the same signing key and obtain an access token.\n\nTo be completely transparent, AI tools helped surface it. However, we have independently reproduced and carefully validated the issue. We follow responsible disclosure practices and are sharing this privately.\n\n### Affected Entrypoints\n\n- `authlib.oauth2.rfc7523.JWTBearerGrant` — default `get_audiences()` returns empty list\n- `authlib.jose.jwt.decode()` with `claims_options` for audience validation\n- `authlib.integrations.flask_oauth2.ResourceProtector.validate_request()` when audience checking is enabled\n\n### Exploit Path\n\n```\n1. Attacker authenticates to Service A (low-privilege)\n2. Authorization server issues JWT with \"aud\": \"https://evil.test/token\"\n3. Attacker presents this assertion to Service B's token endpoint\n4. Service B uses default JWTBearerGr","public_affected_ranges":["< 1.9.0"]}],"null_published_at":"2026-10-31T22:13:31.285Z","source_updated_at":"2026-10-27T15:39:10.000Z","source_disclosed_at":"2026-10-27T15:39:08.000Z","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":"2026-10-31T21:56:51.534Z"}],"next_cursor":null,"snapshot_revision":"42594"}