undici vulnerable to Denial of Service via unhandled error on excessive content-encodings

### Impact undici's `fetch()` crashes the Node.js process when a malicious server returns a response with more than five content codings and closes the connection before sending the body. undici rejects such responses (a content-encoding limit), but it created the internal response stream before that check and returned without attaching an error listener or aborting the request. The early close then surfaces a content-length mismatch on that orphaned internal stream, which Node.js treats as an unhandled `error` and terminates the process. A remote, unauthenticated server can trigger this with a single response, even when the application correctly catches the `fetch()` rejection. undici 6.x, 7.x, and 8.x are affected. ### Patches Upgrade to `6.29.1`, `7.30.1`, or `8.12.2`. undici now validates the content-encoding chain before creating the internal body stream and aborts the response when the limit is exceeded, so no error can surface on an orphaned stream. ### Workarounds None.

Source published

23 Oct 2026 22:14:31 UTC

Source modified

23 Oct 2026 22:30:05 UTC

Observed here

24 Oct 2026 13:17:17 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Publisher rating · HIGH