Vulnerability 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.
CVSS Score
LOW
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nodejs | Undici | < 6.27.0 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlVendor Advisory
- https://github.com/nodejs/undici/security/advisories/GHSA-35p6-xmwp-9g52MitigationVendor Advisory
- https://hackerone.com/reports/3582376Issue Tracking
FAQ
What is CVE-2026-6733?
CVE-2026-6733 is a vulnerability with a CVSS score of 3.7 (LOW). 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...
How severe is CVE-2026-6733?
CVE-2026-6733 has been rated LOW with a CVSS base score of 3.7/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-6733?
Check the references section above for vendor advisories and patch information. Affected products include: Nodejs Undici.