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.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-109869US | — | — | ||
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 pro… | ||||
references
External citations — patches, advisories, analysis.
- https://cna.openjsf.org/security-advisories.htmlWEB
- https://github.com/nodejs/undiciPACKAGE
- https://github.com/nodejs/undici/commit/07ded4941b1e72afec862958c3b8ddf468f3b429WEB
- https://github.com/nodejs/undici/commit/1325a87dfb3492f8e87e6b0a84b3bda4e82e3436WEB
- https://github.com/nodejs/undici/commit/b5084c7dc239172d75c336b1cd51ddac023938a5WEB
- https://github.com/nodejs/undici/releases/tag/v6.29.1WEB
- https://github.com/nodejs/undici/releases/tag/v7.30.1WEB
- https://github.com/nodejs/undici/releases/tag/v8.12.2WEB
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