Riskcovery

CVE-2026-6733

undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse

State
Published
Severity
3.7 Low
Published
Jun 17, 2026
Updated
Jun 17, 2026
Reserved
Apr 20, 2026

Read the record on cve.org

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 v6.26.0, v7.28.0 or v8.5.0.

Workarounds: Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.

Scores

CVSSScoreVectorSource
3.13.7 LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:Nopenjs

Weaknesses

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

Affected Products

ProductVersions
undiciundici
  • before 6.26.0Affected
  • 6.26.0Not affected
  • 7.0.0 to before 7.28.0Affected
  • 7.28.0Not affected
  • 8.0.0 to before 8.5.0Affected
  • 8.5.0Not affected

References

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