CVE-2026-55655

medium

Description

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

References

https://bugzilla.redhat.com/show_bug.cgi?id=2462250

https://access.redhat.com/security/cve/CVE-2026-55655

https://access.redhat.com/errata/RHSA-2026:36759

Details

Source: Mitre, NVD

Published: 2026-06-23

Updated: 2026-07-08

Risk Information

CVSS v2

Base Score: 5.6

Vector: CVSS2#AV:L/AC:L/Au:N/C:C/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 6.1

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

Severity: Medium

EPSS

EPSS: 0.0009