CVE-2026-66339

MEDIUM
MEDIUM Priority: 0.02 BB Relevance: 63/100
Published: 2026-07-24 Modified: 2026-11-05 First seen: 2026-11-05 Status: active

Attack Surface

Network Low Complexity No Auth Conf. Impact

CVSS Vector Breakdown

AV: Network
AC: Low
PR: None
UI: Required
S: Unchanged
C: High
I: None
A: None

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.

References & Advisories (2)

https://bugzilla.redhat.com/show_bug.cgi?id=2506951
issue-tracking x_refsource_REDHAT

Bug Bounty Relevance

63 / 100
✓ Network accessible
✓ No authentication
✓ Low complexity

CVSS Score

6.5 / 10.0 v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N

EPSS — Exploitation Probability

0.25%
Raw Score 0.002490
Percentile 16.3%
Date 2026-11-13

EPSS Trend

2026-11-13
0.00249
2026-11-12
0.00249
2026-11-10
0.00249
2026-11-09
0.00249
2026-11-08
0.00249
2026-11-07
0.00249
2026-11-06
0.00249
2026-11-05
0.00249

Intelligence Sources

mitre ref →
nvd ref →