6.5

CVE-2026-66339: gnome libsoup

CVSS: 6.5v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-66339DEBIAN-CVE-2026-66339
Published 24-07-2026Last modified 28-07-2026
Open JSON

Vulnerability summary

CVE-2026-66339 is a medium (CVSS 6.5) vulnerability in gnome libsoup. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.1% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
36/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.25%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 6 · Related 6
OPENSUSE-SU-2026:12084-1SUSE-SU-2026:4557-1SUSE-SU-2026:4558-1SUSE-SU-2026:4690-1SUSE-SU-2026:4703-1USN-8890-1

Timeline

  1. 24-07-2026
    PublishedVulnerability first disclosed.
  2. 28-07-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.25%

Chance of exploitation in the next 30 days

Percentile

15%

Versus all other CVEs

30-day change

+0.02 pp

From 0.23% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.25%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • referenceUnverified

    Exploit Reference (bugzilla.redhat.com)

    Maturity: unknown

Weaknesses

CWE · root cause

Affected systems

Debian2 products
  • libsoup2.4All versions (No fix recorded)
  • libsoup3All versions (No fix recorded) | < 3.8.0-1
Ubuntu2 products
  • libsoup2.4< 2.52.2-1ubuntu0.3+esm8 | < 2.62.1-1ubuntu0.4+esm9 | < 2.70.0-1ubuntu0.5+esm4 | < 2.74.2-3ubuntu0.9 | < 2.74.3-6ubuntu1.9 | All versions (No fix recorded) | < 2.74.3-10.1ubuntu5+esm3
  • libsoup3< 3.0.7-0ubuntu1+esm9 | < 3.4.4-5ubuntu0.9 | All versions (No fix recorded) | < 3.6.6-1ubuntu0.1
Gnome1 product
Redhat1 product

4 vendors · 6 products

References

7 links