CVE-2026-66339

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

24/07/2026

Last modified:

28/07/2026

Description

A flaw was found in libsoup. After a CONNECT tunnel is established through an HTTP proxy, libsoup incorrectly attaches the Proxy-Authorization header to subsequent HTTPS requests sent through that tunnel to the destination server. This allows the destination server to capture proxy credentials, leading to information disclosure.

Impact

Vector 3.x

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 6.50 MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

Attack Vector (AV): Network
Attack Complexity (AC): Low
Privileges Required (PR): None
User Interaction (UI): Required
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x

6.50

Severity 3.x

MEDIUM

References to Advisories, Solutions, and Tools

https://access.redhat.com/security/cve/CVE-2026-66339
https://bugzilla.redhat.com/show_bug.cgi?id=2506951