{"id":"GHSA-8xcm-r25x-g524","summary":"undici vulnerable to downstream response desynchronization via retry interceptor","details":"### Impact\n\nUndici's `interceptors.retry()` can deliver a response whose body length does not match the `Content-Length` header exposed to the application after a retry or resume of a partial response. Applications that use `interceptors.retry()` and forward upstream response headers and bodies downstream, for example proxy or gateway applications, may emit an invalid HTTP response with a stale `Content-Length` header. This can lead to downstream response desynchronization, connection hangs, or response corruption in clients or intermediaries that rely on the forwarded framing metadata.\n\nA malicious or faulty upstream can respond to a range request with a `206 Partial Content` response such as:\n\n```http\nContent-Range: bytes 0-99/300\nContent-Length: 300\n```\n\nand then send only 99 bytes before closing the socket. `interceptors.retry()` can then retry with `Range: bytes=99-99`, receive the final byte, and deliver a 100-byte body to the application while the response headers still contain `Content-Length: 300` from the first response.\n\nThe bug requires `interceptors.retry()` to be enabled, an upstream that returns a partial response with a mismatched framing header, and a downstream forwarder that does not remove or recalculate `Content-Length`.\n\n### Patches\n\nPatched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later.\n\n### Workarounds\n\n- Disable `interceptors.retry()` for untrusted upstreams.\n- Remove or recalculate `Content-Length` before forwarding a response body assembled or transformed by Undici.","aliases":["CVE-2026-16728"],"modified":"2026-08-03T19:30:08.037674954Z","published":"2026-08-03T19:24:33Z","database_specific":{"github_reviewed_at":"2026-08-03T19:24:33Z","nvd_published_at":"2026-07-29T21:17:46Z","cwe_ids":["CWE-444"],"severity":"MODERATE","github_reviewed":true},"references":[{"type":"WEB","url":"https://github.com/nodejs/undici/security/advisories/GHSA-8xcm-r25x-g524"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-16728"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/1b5a5312c3a7d7a30c31bf0d000b39a8a2531e1c"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/2b3f749336d356bbbc50192f87f6cf7bc714721a"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/4a9dafb16ff43880cf590e6d9c2aeee25fbff6d7"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/4fd5a0c61e627f928b7003adc4ffe1e55ec63420"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/cba3a52ac2e7abcc4e656d82af8579ea82c2bb9e"},{"type":"WEB","url":"https://github.com/nodejs/undici/commit/e11a68ed4ff345c79402476f7a00d473443e318d"},{"type":"WEB","url":"https://hackerone.com/reports/3828685"},{"type":"WEB","url":"https://cna.openjsf.org/security-advisories.html"},{"type":"PACKAGE","url":"https://github.com/nodejs/undici"},{"type":"WEB","url":"https://github.com/nodejs/undici/releases/tag/v6.28.0"},{"type":"WEB","url":"https://github.com/nodejs/undici/releases/tag/v7.29.0"},{"type":"WEB","url":"https://github.com/nodejs/undici/releases/tag/v8.9.0"}],"affected":[{"package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"6.28.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8xcm-r25x-g524/GHSA-8xcm-r25x-g524.json"}},{"package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"7.0.0"},{"fixed":"7.29.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8xcm-r25x-g524/GHSA-8xcm-r25x-g524.json"}},{"package":{"name":"undici","ecosystem":"npm","purl":"pkg:npm/undici"},"ranges":[{"type":"SEMVER","events":[{"introduced":"8.0.0"},{"fixed":"8.9.0"}]}],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/08/GHSA-8xcm-r25x-g524/GHSA-8xcm-r25x-g524.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N"}]}