CVE-2026-6734
Description
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.
Statement
This is rated as an Important security flaw. The undici library, when configured with Socks5ProxyAgent to handle requests for multiple origins, incorrectly reuses connection pools. This can lead to sensitive data and credentials being misrouted to unintended destinations, potentially downgrading HTTPS connections to HTTP and compromising data integrity and confidentiality. Red Hat products utilizing undici with Socks5ProxyAgent in multi-origin scenarios are affected.
Mitigation
The single most impactful mitigation is applying network egress controls to restrict which external destinations affected applications can reach. Because the vulnerability causes requests to be misrouted to wrong origins, limiting the set of reachable origins directly reduces the attack surface. These controls collectively limit the blast radius of the connection pool misrouting — the attacker must compromise one of the explicitly allowed destinations rather than any arbitrary origin — but they do not fix the underlying logic bug.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 7.5 | 8.8 | 7.5 |
| Attack Vector | Network | Network | Network |
| Attack Complexity | High | Low | High |
| Privileges Required | Low | Low | Low |
| User Interaction | None | None | None |
| Scope | Unchanged | Unchanged | Unchanged |
| Confidentiality | High | High | High |
| Integrity Impact | High | High | High |
| Availability Impact | High | High | High |
Vector
Red Hat: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
cve.org: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Understanding the Weakness (CWE)
Access Control,Other
Technical Impact: Gain Privileges or Assume Identity; Varies by Context; Bypass Protection Mechanism
An attacker can access any functionality that is inadvertently accessible to the source.
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