Bug 2490024 (CVE-2026-6734)

Summary: CVE-2026-6734 undici: undici: Information disclosure and data integrity issues due to incorrect Socks5ProxyAgent connection routing
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: aazores, abarbaro, alizardo, ataylor, cdrage, cmah, dbruscin, dschmidt, eaguilar, ebaron, ehugonne, erezende, jchui, jhe, jkoehler, jlanda, jolong, kaycoth, kshier, ktsao, kvanderr, lphiri, manissin, nboldt, oaljalju, pjindal, psrna, rhel-process-autobot, rushinde, sdawley, simaishi, smcdonal, stcannon, teagle, watson-tool-maintainers, yguenane
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in undici. When using Socks5ProxyAgent, undici incorrectly reuses a single connection pool across different origins. This can lead to cross-origin request routing, where sensitive credentials and data intended for one destination are sent to another. Consequently, responses from unintended origins may be trusted, and secure HTTPS connections could be silently downgraded to unencrypted HTTP, resulting in information disclosure and data integrity issues.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Bug Depends On: 2490192, 2490195, 2490198, 2490199    
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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.
Comment 5 errata-xmlrpc 2026-07-06 04:36:56 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:35841 https://access.redhat.com/errata/RHSA-2026:35841
Comment 6 errata-xmlrpc 2026-07-06 14:23:44 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:35891 https://access.redhat.com/errata/RHSA-2026:35891
Comment 7 errata-xmlrpc 2026-07-15 11:23:24 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:39868 https://access.redhat.com/errata/RHSA-2026:39868
Comment 8 errata-xmlrpc 2026-07-29 19:55:46 UTC 
This issue has been addressed in the following products:

  Cryostat 4 on RHEL 9

Via RHSA-2026:48151 https://access.redhat.com/errata/RHSA-2026:48151