CVE-2026-6734

undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse

Published Jun 17, 2026 CVSS 3.1 · 7.5 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-hm92-r4w5-c3mj undici vulnerable to cross-origin request routing via SOCKS5 proxy pool reuse
History
Type Values Removed Values Added
First Time appeared Undici
Undici undici
Vendors & Products Undici
Undici undici
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

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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
openjs
Published
Updated
Sep 10, 2026, 12:05 PM
Reserved
Apr 20, 2026, 10:57 PM
Status
Modified
Published
Jun 17, 2026, 6:18 PM
Modified
Sep 10, 2026, 1:20 PM
Severity
Important
Public date
Jun 17, 2026, 4:36 PM