undici vulnerable to response truncation via oversized chunked responses in the dump interceptor
What fixes it
- 7.29.1undici, npmGitHub
npm install undici@7.29.1 - 8.10.2undici, npmGitHub
npm install undici@8.10.2 - 7.29.1undiciCVE List
- 8.10.2undiciCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
Description
Impact
undici's interceptors.dump() reads and discards response bodies up to a configurable maxSize. When a response declares a Content-Length that exceeds maxSize, the request is aborted cleanly. When a response is sent chunked (no Content-Length) and its body exceeds maxSize, it is not aborted: the interceptor ends the response early once the accumulated size reaches maxSize, and continued delivery from the parser triggers an internal assertion that is caught and turned into a request abort and connection tear-down. The application observes a misleading 200 with an empty or truncated body while the connection is disconnected. Any application using the dump interceptor against untrusted or misbehaving upstreams is affected.
Patches
Upgrade to 7.29.1 or 8.10.2. The dump interceptor now enforces maxSize on both the declared and the received body size, aborting the request with a RequestAbortedError instead of returning a truncated response.
Workarounds
None. Avoid using interceptors.dump() with untrusted upstreams until upgraded.
Text from GitHub Advisory Database
Affected versions 8
- undici, npm>= 7.1.0, < 7.29.1GitHub
- undici, npm>= 8.0.0, < 8.10.2GitHub
- undiciaffected: 7.1.0 before 7.29.1CVE List
- undiciunaffected: 7.29.1CVE List
- undiciaffected: 8.0.0 before 8.10.2CVE List
- undiciunaffected: 8.10.2CVE List
- undici, npmfrom 7.1.0, fixed in 7.29.1OSV
- undici, npmfrom 8.0.0, fixed in 8.10.2OSV
References 8
- github.com/nodejs/undici/commit/21693f406f0142f3504192e9f9b022dcf84782aeFixvia GitHub
- github.com/nodejs/undici/commit/6d583124e7cf60b640097d64144ed633cc450584Fixvia GitHub
- github.com/nodejs/undici/releases/tag/v7.29.1Fixvia GitHub
- github.com/nodejs/undici/releases/tag/v8.10.2Fixvia GitHub
- github.com/nodejs/undici/security/advisories/GHSA-2gqq-gqf2-x968Advisoryvia CVE List
- cna.openjsf.org/security-advisories.htmlAdvisoryvia CVE List
- github.com/advisories/GHSA-2gqq-gqf2-x968Advisoryvia GitHub
- nvd.nist.gov/vuln/detail/CVE-2026-84947Referencevia GitHub