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.

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Fixes

Solution

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Workaround

No workaround given by the vendor.

History

Thu, 18 Jun 2026 16:45:00 +0000

Type Values Removed Values Added
First Time appeared Redhat
Redhat hummingbird
Weaknesses CWE-940
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat
Redhat hummingbird
References
Metrics threat_severity

None

threat_severity

Important


Thu, 18 Jun 2026 04:45:00 +0000

Type Values Removed Values Added
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.
Title undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse
Weaknesses CWE-346
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: openjs

Published:

Updated: 2026-06-17T18:26:51.736Z

Reserved: 2026-04-20T22:57:40.878Z

Link: CVE-2026-6734

cve-icon Vulnrichment

Updated: 2026-06-17T18:26:47.055Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-17T16:36:55Z

Links: CVE-2026-6734 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses