Published At-17 Jun, 2026 | 18:18
Updated At-23 Jun, 2026 | 05:17
Impact:
undici's ProxyAgent silently drops the requestTls option when configured with a SOCKS5 proxy URI (socks5:// or socks://). The target HTTPS connection through the SOCKS5 tunnel falls back to Node's default trust store, ignoring user-configured ca, cert, key, rejectUnauthorized, and servername settings.
Applications that pin to an internal or corporate CA via requestTls.ca will, when their proxy URI is SOCKS5, get the default Mozilla CA bundle as the trust anchor instead. Any cert signed by any publicly-trusted CA for the target hostname is accepted, breaking the intended pin and enabling MITM read and tamper of the HTTPS exchange.
Affected applications are those that use undici's ProxyAgent (or Socks5ProxyAgent directly) with SOCKS5 AND rely on requestTls for TLS scope restriction. The bug was introduced in undici 7.23.0 when SOCKS5 support was added.
Patches:
Upgrade to undici v7.28.0 or v8.5.0.
Workarounds:
No workaround is available within the SOCKS5 path. If a SOCKS5 proxy with TLS scope restriction is required and an upgrade is not yet possible, route the traffic through an HTTP-proxy ProxyAgent instead, where requestTls is honored correctly.
CISA Catalog
| Date Added | Due Date | Vulnerability Name | Required Action |
|---|
| N/A | | |
Date Added: N/A
Due Date: N/A
Vulnerability Name: N/A
Required Action: N/A
Metrics
| Type | Version | Base score | Base severity | Vector |
|---|
| Secondary | 3.1 | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| | | N/A | |
Type: Secondary
Version: 3.1
Base score: 7.4
Base severity: HIGH
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Type: N/A
Version:
Base score:
Base severity: N/A
Weaknesses
| CWE ID | Type | Source |
|---|
| CWE-295 | Secondary | ce714d77-add3-4f53-aff5-83d477b104bb |
Type: Secondary
Source: ce714d77-add3-4f53-aff5-83d477b104bb
Change History
0Changes found