LowGHSA-2gqq-gqf2-x968CVE-2026-84947

undici vulnerable to response truncation via oversized chunked responses in the dump interceptor

Published 29 Sept 2026 · Updated 29 Sept 2026

Affected packages

Affected
>=7.1.0 <7.29.1
Fixed in
7.29.1
Update to the fixed version for your release line, for example:npm install undici@7.29.1
Affected
>=8.0.0 <8.10.2
Fixed in
8.10.2
Update to the fixed version for your release line, for example:npm install undici@8.10.2

Details

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.

Is GHSA-2gqq-gqf2-x968 in any of your client repos?

Checking one package by hand is fine. Checking it across forty client projects is not. NPMscan reads the lockfiles in every GitHub repo you pick, finds each project with an affected undici, and gives you the command that fixes it.

References

Advisory data from OSV.dev (opens OSV.dev in a new tab), refreshed daily.