CVE-2026-66339

EUVD-2026-48751
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
NISTPrimary
6.5 MEDIUM
NETWORK
LOW
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
Base Score
CVSS 3.x
EPSS Score
Percentile: 13.31%
Affected Products (NVD)
VendorProductVersion
gnomelibsoup
-
redhatenterprise_linux
6.0
redhatenterprise_linux
7.0
redhatenterprise_linux
8.0
redhatenterprise_linux
9.0
redhatenterprise_linux
10.0
𝑥
= Vulnerable software versions
Debian logo
Debian Releases
Debian Product
Codename
libsoup2.4
bookworm
vulnerable
trixie
no-dsa
libsoup3
bookworm
vulnerable
forky
vulnerable
sid
vulnerable
trixie
no-dsa
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
libsoup2.4
bionic
needs-triage
focal
needs-triage
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
xenial
needs-triage
libsoup3
jammy
needs-triage
noble
needs-triage
resolute
needs-triage
Common Weakness Enumeration
References
https://access.redhat.com/security/cve/CVE-2026-66339
https://bugzilla.redhat.com/show_bug.cgi?id=2506951