CVE-2026-109869
undici is an HTTP client library for Node.js. In versions 6.23.0 through 6.29.0, 7.18.0 through 7.30.0, and 8.0.0 through 8.12.1, its fetch() implementation 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 because of 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, so the early close surfaces a content-length mismatch on the orphaned 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, resulting in a denial of service. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, and users should upgrade to one of those versions or later. There is no workaround.
- Score
- CVSS 3.1 7.5 High
- Status
- Analyzed - ce714d77-add3-4f53-aff5-83d477b104bb
- Published
- 2026-10-15
- Last modified
- 2026-10-19
- Weaknesses
- CWE-248, CWE-459
Affected products
References
- https://github.com/nodejs/undici/security/advisories/GHSA-xjj6-f33q-929c
- https://cna.openjsf.org/security-advisories.html
