CVE-2026-6733Low· 3.7▾ Sunlitundici vulnerable to HTTP response queue poisoning via keep-alive socket reuse
▾ Sunlit zone — Low / medium · no exploitation signal
impact 20.4 · likelihood 0 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 4.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via GHSA
0.2%
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.
Upgrade to undici v6.27.0, v7.28.0 or v8.5.0.
Disable keep-alive connection reuse by setting keepAliveTimeout: 0 on the Client or Pool.
undici < 6.27.0undici >= 7.0.0, < 7.28.0undici >= 8.0.0, < 8.5.0Upgrade to a patched release:
undici 6.27.0undici 7.28.0undici 8.5.0Connected by shared product, vendor, weakness, or advisory.
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