CVE-2026-66339 PUBLISHED

Libsoup: libsoup: proxy credentials leak to destination server via proxy-authorization header in connect tunnels

Assigner: redhat
Reserved: 24.07.2026 Published: 24.07.2026 Updated: 24.07.2026

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.

Metrics

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
CVSS Score: 6.5

Product Status

Vendor Red Hat
Product Red Hat Enterprise Linux 10
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 6
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 7
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 9
Versions Default: affected

Credits

  • Upstream acknowledges cavid as the original reporter.

References

Problem Types

  • Insertion of Sensitive Information Into Sent Data CWE