---
id: CVE-2026-55655
title: A flaw was found in OpenSSH
summary: >-
  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 …
severity: medium
cvss: 5
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N'
cwe:
  - CWE-923
vendor: openbsd
product: openssh
affected:
  - openssh
  - enterprise_linux = 6.0
  - enterprise_linux = 7.0
  - enterprise_linux = 8.0
  - enterprise_linux = 9.0
  - enterprise_linux = 10.0
published: '2026-06-23'
updated: '2026-10-06'
sourceUpdated: '2026-10-06T16:17:08.293'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-55655'
references:
  - url: 'https://access.redhat.com/errata/RHSA-2026:36759'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:47755'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:47756'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:47757'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:54387'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:58981'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:76748'
    label: secalert@redhat.com
  - url: 'https://access.redhat.com/security/cve/CVE-2026-55655'
    label: secalert@redhat.com
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2462250'
    label: secalert@redhat.com
tags:
  - nvd
  - cve.org
epss: 0.00124
epssPercentile: 0.01873
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-06-23T12:21:42.502865Z'
ingestedAt: '2026-10-06T16:04:04.488Z'
---

## Overview

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.

## Affected

- `openssh`
- `enterprise_linux = 6.0`
- `enterprise_linux = 7.0`
- `enterprise_linux = 8.0`
- `enterprise_linux = 9.0`
- `enterprise_linux = 10.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.