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
Awaiting analysis
This vulnerability is currently awaiting analysis.
Base Score
CVSS 3.x
EPSS Score
Percentile: 13%
Debian logo
Debian Releases
Debian Product
Codename
libsoup2.4
bookworm
vulnerable
bullseye
vulnerable
bullseye (security)
vulnerable
trixie
vulnerable
libsoup3
bookworm
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
Common Weakness Enumeration
References
https://access.redhat.com/security/cve/CVE-2026-66339
https://bugzilla.redhat.com/show_bug.cgi?id=2506951