GHSA-8xcm-r25x-g524

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GHSA-8xcm-r25x-g524

Summary: undici vulnerable to downstream response desynchronization via retry interceptor

Details: ### Impact Undici'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. A malicious or faulty upstream can respond to a range request with a `206 Partial Content` response such as: ```http Content-Range: bytes 0-99/300 Content-Length: 300 ``` and 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. The 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`. ### Patches Patched in undici v6.28.0, v7.29.0, and v8.9.0. Users should upgrade to one of these versions or later. ### Workarounds - Disable `interceptors.retry()` for untrusted upstreams. - Remove or recalculate `Content-Length` before forwarding a response body assembled or transformed by Undici.

References: https://github.com/nodejs/undici/security/advisories/GHSA-8xcm-r25x-g524, https://nvd.nist.gov/vuln/detail/CVE-2026-16728, https://github.com/nodejs/undici/commit/1b5a5312c3a7d7a30c31bf0d000b39a8a2531e1c, https://github.com/nodejs/undici/commit/2b3f749336d356bbbc50192f87f6cf7bc714721a, https://github.com/nodejs/undici/commit/4a9dafb16ff43880cf590e6d9c2aeee25fbff6d7, https://github.com/nodejs/undici/commit/4fd5a0c61e627f928b7003adc4ffe1e55ec63420, https://github.com/nodejs/undici/commit/cba3a52ac2e7abcc4e656d82af8579ea82c2bb9e, https://github.com/nodejs/undici/commit/e11a68ed4ff345c79402476f7a00d473443e318d, https://hackerone.com/reports/3828685, https://cna.openjsf.org/security-advisories.html, https://github.com/nodejs/undici, https://github.com/nodejs/undici/releases/tag/v6.28.0, https://github.com/nodejs/undici/releases/tag/v7.29.0, https://github.com/nodejs/undici/releases/tag/v8.9.0