undici up to 7.25.x/8.1.x Destination origin validation

Summaryinfo

A vulnerability was found in undici up to 7.25.x/8.1.x. It has been classified as problematic. Affected by this vulnerability is an unknown functionality of the component Destination Handler. This manipulation causes origin validation. This vulnerability is tracked as CVE-2026-6734. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as problematic was found in undici up to 7.25.x/8.1.x. Affected by this vulnerability is an unknown code block of the component Destination Handler. The manipulation with an unknown input leads to a origin validation vulnerability. The CWE definition for the vulnerability is CWE-346. The product does not properly verify that the source of data or communication is valid. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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.

The weakness was disclosed by deepview-autofix as GHSA-hm92-r4w5-c3mj. The advisory is shared at github.com. This vulnerability is known as CVE-2026-6734 since 04/21/2026. The exploitation appears to be difficult. The attack can be launched remotely. Neither technical details nor an exploit are publicly available.

Upgrading to version 7.26.0 or 8.2.0 eliminates this vulnerability.

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Productinfo

Name

• undici

Version

• 7.0
• 7.1
• 7.2
• 7.3
• 7.4
• 7.5
• 7.6
• 7.7
• 7.8
• 7.9
• 7.10
• 7.11
• 7.12
• 7.13
• 7.14
• 7.15
• 7.16
• 7.17
• 7.18
• 7.19
• 7.20
• 7.21
• 7.22
• 7.23
• 7.24
• 7.25
• 8.0
• 8.1

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CPE 2.2info

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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