Improper Restriction of Communication Channel to Intended Endpoints Affecting openssh-keycat-debuginfo package, versions <0:9.9p1-10.amzn2023.0.1


Severity

Recommended
0.0
medium
0
10

Based on Amazon Linux security rating.

Threat Intelligence

EPSS
0.09% (1st percentile)

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  • Snyk IDSNYK-AMZN2023-OPENSSHKEYCATDEBUGINFO-18530756
  • published5 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 Amazon-Linux:2023 openssh-keycat-debuginfo to version 0:9.9p1-10.amzn2023.0.1 or higher.
This issue was patched in ALAS2023-2026-2031.

NVD Description

Note: Versions mentioned in the description apply only to the upstream openssh-keycat-debuginfo package and not the openssh-keycat-debuginfo package as distributed by Amazon-Linux. See How to fix? for Amazon-Linux:2023 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.

CVSS Base Scores

version 3.1