Vulnerability Description
Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying that the pool's origin matches the requested origin. All requests are dispatched through the pool connected to the first origin, regardless of the intended destination. This causes cross-origin request routing: credentials and request data intended for origin B are sent to origin A, responses from the wrong origin are trusted, and HTTPS requests may be silently downgraded to HTTP. Impacted users are applications that use Socks5ProxyAgent (directly or via setGlobalDispatcher) and make requests to more than one origin. This was introduced in undici 7.23.0 via PR #4385 and affects all versions through 8.1.0. Patches: Upgrade to undici v7.26.0 or v8.2.0. Workarounds: Use a separate Socks5ProxyAgent instance per origin, or avoid using Socks5ProxyAgent with multiple origins.
CVSS Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Nodejs | Undici | >= 7.23.0, < 7.28.0 |
Related Weaknesses (CWE)
References
- https://cna.openjsf.org/security-advisories.htmlVendor Advisory
- https://github.com/nodejs/undici/security/advisories/GHSA-hm92-r4w5-c3mjMitigationVendor Advisory
- https://access.redhat.com/errata/RHSA-2026:22380
- https://access.redhat.com/errata/RHSA-2026:22934
- https://access.redhat.com/errata/RHSA-2026:34342
- https://access.redhat.com/errata/RHSA-2026:35841
- https://access.redhat.com/errata/RHSA-2026:35891
- https://access.redhat.com/errata/RHSA-2026:36754
- https://access.redhat.com/errata/RHSA-2026:36820
- https://access.redhat.com/errata/RHSA-2026:38236
- https://access.redhat.com/errata/RHSA-2026:39868
- https://access.redhat.com/errata/RHSA-2026:41929
- https://access.redhat.com/errata/RHSA-2026:48124
- https://access.redhat.com/errata/RHSA-2026:48151
- https://access.redhat.com/errata/RHSA-2026:56366
FAQ
What is CVE-2026-6734?
CVE-2026-6734 is a vulnerability with a CVSS score of 7.5 (HIGH). Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying that the pool's origin matches the requested origin. All requests are dispatched ...
How severe is CVE-2026-6734?
CVE-2026-6734 has been rated HIGH with a CVSS base score of 7.5/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-6734?
Check the references section above for vendor advisories and patch information. Affected products include: Nodejs Undici.