GitHub Advisoryadvisory · npm
GHSA-35p6-xmwp-9g52 undici vulnerable to HTTP response queue poisoning via keep-alive socket reuse
LOW
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
- https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52 web
- https://nvd.nist.gov/vuln/detail/CVE-2026-6733 advisory
- https://github.com/nodejs/undici/commit/6ea54ef8c4051e95bb68c89d4a5c9274fe6fbb4b web
- https://hackerone.com/reports/3582376 web
- https://cna.openjsf.org/security-advisories.html web
- https://github.com/nodejs/undici package
- https://github.com/nodejs/undici/releases/tag/v6.27.0 web
- https://github.com/nodejs/undici/releases/tag/v7.28.0 web
- https://github.com/nodejs/undici/releases/tag/v8.5.0 web