Bug 2490024 (CVE-2026-6734) - CVE-2026-6734 undici: undici: Information disclosure and data integrity issues due to incorrect Socks5ProxyAgent connection routing
Summary: CVE-2026-6734 undici: undici: Information disclosure and data integrity issue...
Keywords:
Status: NEW
Alias: CVE-2026-6734
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On: 2490192 2490195 2490198 2490199
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-06-17 19:04 UTC by OSIDB Bzimport
Modified: 2026-06-17 23:22 UTC (History)
35 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)

Description OSIDB Bzimport 2026-06-17 19:04:24 UTC 
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.
Note You need to log in before you can comment on or make changes to this bug.