GitHub Advisoryadvisory · npm

GHSA-35p6-xmwp-9g52 undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

LOW Published 2026-06-19 Modified 2026-08-05 Official page ↗
Aliases
CVE-2026-6733
Ecosystem
npm
Packages
undici
Severity
Low
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weaknesses
CWE-367
Reviewed
2026-06-19

Affected packages

• npm undici: < 6.27.0 → fixed in 6.27.0 • npm undici: >= 7.0.0, < 7.28.0 → fixed in 7.28.0 • npm undici: >= 8.0.0, < 8.5.0 → fixed in 8.5.0

Description

Impact Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. An attacker-controlled upstream server can inject an unsolicited HTTP/1.1 response onto an idle socket after a request completes. When the client dispatches the next request on that socket, it associates the injected response with the new request, causing responses to be delivered to the wrong requests. This requires an attacker-controlled or compromised upstream HTTP/1.1 server and keep-alive connection reuse. Patches Upgrade to undici v6.27.0, v7.28.0 or v8.5.0. Workarounds Disable keep-alive connection reuse by setting `keepAliveTimeout: 0` on the Client or Pool.

Related

Alias · CVE (1)

  • CVE-2026-6733 Impact: Undici's HTTP/1.1 client is vulnerable to response queue poisoning on reused keep-alive sockets. vulnerability

Weakness · CWE (1)

  • CWE-367 Time-of-check Time-of-use (TOCTOU) Race Condition weakness

References