Improper Restriction of Communication Channel to Intended Endpoints Affecting openssh-keycat package, versions <0:9.9p1-9.0.1.el9_8


Severity

Recommended
high

Based on Oracle Linux security rating.

Threat Intelligence

EPSS
0.14% (3rd percentile)

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  • Snyk IDSNYK-ORACLE9-OPENSSHKEYCAT-18786542
  • published14 Aug 2026
  • disclosed23 Jun 2026

Introduced: 23 Jun 2026

CVE-2026-55655  (opens in a new tab)
CWE-923  (opens in a new tab)

How to fix?

Upgrade Oracle:9 openssh-keycat to version 0:9.9p1-9.0.1.el9_8 or higher.
This issue was patched in ELSA-2026-47756.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssh-keycat package and not the openssh-keycat package as distributed by Oracle. See How to fix? for Oracle:9 relevant fixed versions and status.

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

CVSS Base Scores

version 3.1