CVE-2026-6734
HIGH 7.5Impact: 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.
Severe if exploited (CVSS 7.5), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
0.3%chance of exploitation in 30 days · 20th percentile
Impact if exploited
7.5CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ⚠Privileges: Requires a low-privilege account
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Affected
Products Undici Red Hat Hardened Images Cryostat 4 Openshift Pipelines Red Hat Build Of Podman Desktop Red Hat Developer Hub Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 8
Weakness (CWE)
- CWE-346
- CWE-940
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
References
Advisories
Technical & other
- https://github.com/nodejs/undici/security/advisories/GHSA-hm92-r4w5-c3mj
- https://cna.openjsf.org/security-advisories.html
- https://access.redhat.com/security/cve/CVE-2026-6734
- https://bugzilla.redhat.com/show_bug.cgi?id=2490024
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-6734.json