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

Description

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.

Scores

EPSS (exploitation in 30 days)

0.34% · top 72% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: yes · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.

Weakness

• CWE-248: Uncaught Exception (opens in a new tab)All about CWE-248 and its CVEs
• CWE-459: Incomplete Cleanup (opens in a new tab)All about CWE-459 and its CVEs

Affected products

• undici · undici

  • affected 6.23.0 – < 6.29.1
  • unaffected 6.29.1
  • affected 7.18.0 – < 7.30.1
  • unaffected 7.30.1
  • affected 8.0.0 – < 8.12.2
  • unaffected 8.12.2

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• npmundiciGHSA-xjj6-f33q-929c (opens in a new tab)

References (2)

• https://github.com/nodejs/undici/security/advisories/GHSA-xjj6-f33q-929c (opens in a new tab)
• https://cna.openjsf.org/security-advisories.html (opens in a new tab)

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-xjj6-f33q-929c (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-109869](https://trackcve.app/badge/CVE-2026-109869.svg)](https://trackcve.app/cve/CVE-2026-109869)

Record last updated 16 Oct 2026, 20:06 UTC.