GitHub Advisoryadvisory · npm
GHSA-hm92-r4w5-c3mj undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse
HIGH
Official page ↗
- Aliases
- CVE-2026-6734
- Ecosystem
- npm
- Packages
- undici
- Severity
- High
- CVSS vector
- CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Weaknesses
- CWE-346
- Reviewed
- 2026-06-19
Affected packages
• npm undici: >= 7.23.0, < 7.28.0 → fixed in 7.28.0
• npm undici: >= 8.0.0, < 8.2.0 → fixed in 8.2.0
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 #4385 and affects all versions through 8.1.0.
Patches
Upgrade to undici v7.28.0 or v8.2.0
Workarounds
Use a separate `Socks5ProxyAgent` instance per origin, or avoid using `Socks5ProxyAgent` with multiple origins.
Related
Alias · CVE (1)
- CVE-2026-6734 Impact: When using Socks5ProxyAgent, undici reuses a single connection pool across different origins without verifying that the pool's… vulnerability
Weakness · CWE (1)
- CWE-346 Origin Validation Error weakness