CVE-2026-55655 — MEDIUM (5.0)

Vulnerability 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.

CVSS Score

5.0

MEDIUM

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

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

LOW

Availability

NONE

Affected Products

Vendor	Product	Versions
Openbsd	Openssh	-
Redhat	Enterprise Linux	6.0

Related Weaknesses (CWE)

CWE-923

References

FAQ

What is CVE-2026-55655?

CVE-2026-55655 is a vulnerability with a CVSS score of 5.0 (MEDIUM). 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 nam...

How severe is CVE-2026-55655?

CVE-2026-55655 has been rated MEDIUM with a CVSS base score of 5.0/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-55655?

Check the references section above for vendor advisories and patch information. Affected products include: Openbsd Openssh, Redhat Enterprise Linux.