{"items":[{"id":"NVI-00012989","kind":"vulnerability","title":"undici vulnerable to downstream response splitting via retry interceptor","revision":2,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-r53p-7pc4-xj5r","CVE-2026-18540"],"plain_summary":"GitHub lists this reviewed advisory for undici, undici, undici. 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-23ff6d135e9c674c378192144d707afa"],"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":"2026-09-29T18:22:08.000Z","value":"3.7 low","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-30e9b2446a63117f1ca2e7519cbc1311"},{"kind":"EPSS","as_of":"2026-11-01T12:00:16.000Z","value":"0.309%","meaning":"FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.23781. Missing scores are unknown.","source_id":"sr-23ff6d135e9c674c378192144d707afa"}],"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-30e9b2446a63117f1ca2e7519cbc1311","url":"https://github.com/advisories/GHSA-r53p-7pc4-xj5r","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-r53p-7pc4-xj5r","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T07:24:25.558Z"},{"id":"sr-23ff6d135e9c674c378192144d707afa","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-2026-18540","publisher":"FIRST EPSS","observed_at":"2026-11-01T14:28:32.270Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":["< 6.28.1"]},{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":[">= 7.0.0, < 7.29.1"]},{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":[">= 8.0.0, < 8.10.2"]}],"null_published_at":"2026-11-04T18:04:03.185Z","source_updated_at":"2026-09-29T18:22:08.000Z","source_disclosed_at":"2026-09-29T18:22:07.000Z","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":"2026-11-01T07:24:25.558Z"},{"id":"NVI-00012989","kind":"vulnerability","title":"undici vulnerable to downstream response splitting via retry interceptor","revision":1,"unknowns":["Customer inventory, deployment, reachability and exploitation have not been inspected."],"lifecycle":"active","identifiers":["GHSA-r53p-7pc4-xj5r","CVE-2026-18540"],"plain_summary":"GitHub lists this reviewed advisory for undici, undici, undici. 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-30e9b2446a63117f1ca2e7519cbc1311"],"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":"2026-09-29T18:22:08.000Z","value":"3.7 low","meaning":"GitHub source severity; exploitability and local consequence require separate evidence.","source_id":"sr-30e9b2446a63117f1ca2e7519cbc1311"}],"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-30e9b2446a63117f1ca2e7519cbc1311","url":"https://github.com/advisories/GHSA-r53p-7pc4-xj5r","basis":"vendor_advisory","notes":"GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.","title":"GHSA-r53p-7pc4-xj5r","publisher":"GitHub Advisory Database","observed_at":"2026-11-01T07:24:25.558Z"}],"affected_context":[{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":["< 6.28.1"]},{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":[">= 7.0.0, < 7.29.1"]},{"certainty":"source_listed","source_ids":["sr-30e9b2446a63117f1ca2e7519cbc1311"],"technology":"undici","known_exclusions":[],"conditions_summary":"### Impact\n\nUndici's `interceptors.retry()` can resume a request after a partial response and append the resumed bytes to an already partially delivered body, while the application still receives the original response's status and headers. When that response carried a `Content-Length`, the application can receive a longer body. Applications that forward Undici's status, headers, and body downstream without recalculating framing, for example proxy or gateway applications, may emit a response whose body exceeds the forwarded `Content-Length`, and the excess bytes can be read as the start of a subsequent HTTP response (downstream response splitting or desynchronization).\n\nFor example, a `404 Not Found` with `Content-Length: 2` that sends one byte then closes can be resumed with an open-ended `Range` request, and the resumed `206 Partial Content` bytes are appended, so the application receives more than two body bytes while still seeing `Content-Length: 2`. The bug requires `interceptors.retry()` enabled, an attacker-controlled or faulty upstream, and a downstream forwarder that does not recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.1, v7.29.1, and v8.10.2. Upgrad","public_affected_ranges":[">= 8.0.0, < 8.10.2"]}],"null_published_at":"2026-11-01T07:29:12.907Z","source_updated_at":"2026-09-29T18:22:08.000Z","source_disclosed_at":"2026-09-29T18:22:07.000Z","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":"2026-11-01T07:24:25.558Z"}],"next_cursor":null,"snapshot_revision":"42594"}