OpenSSH X11 Forwarding Hijack via local X Socket Pre-binding
CVE-2026-55655 Published on June 23, 2026

Openssh: local mitm of x11 forwarding via abstract unix socket pre-binding in red hat enterprise linux openssh client versions
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.

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Vulnerability Analysis

CVE-2026-55655 can be exploited with local system access, requires user interaction and a small amount of user privileges. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have a high impact on confidentiality, with no impact on integrity, and no impact on availability.

Attack Vector:
LOCAL
Attack Complexity:
HIGH
Privileges Required:
LOW
User Interaction:
REQUIRED
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
LOW
Availability Impact:
NONE

Timeline

Reported to Red Hat.

Made public. 57 days later.

Weakness Type

Improper Restriction of Communication Channel to Intended Endpoints

The software establishes a communication channel to (or from) an endpoint for privileged or protected operations, but it does not properly ensure that it is communicating with the correct endpoint.


Products Associated with CVE-2026-55655

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Red Hat Enterprise Linux (RHEL)
 
Red Hat Hummingbird
 
Red Hat Openshift
 
Red Hat Rhui
 
Red Hat Enterprise Linux Eus
 
Red Hat Rhel E4s
 
Red Hat Rhel Eus
 
Red Hat Openshift Ai
 

Affected Versions

Red Hat Enterprise Linux 10: Red Hat Enterprise Linux 10.0 Extended Update Support: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9: Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions: Red Hat Enterprise Linux 9.6 Extended Update Support: Red Hat Hardened Images: Red Hat OpenShift AI 3.0: Red Hat OpenShift AI 3.0: Red Hat OpenShift AI 3.0: Red Hat OpenShift AI 3.0: Red Hat OpenShift AI 3.0: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.2: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.3: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.4: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat OpenShift AI 3.5: Red Hat Update Infrastructure 5: Red Hat Update Infrastructure 5: Red Hat Update Infrastructure 5: Red Hat Update Infrastructure 5: Red Hat Enterprise Linux 6: Red Hat Enterprise Linux 7: Red Hat OpenShift Container Platform 4: Red Hat OpenShift Container Platform 4:

Exploit Probability

EPSS
0.09%
Percentile
0.50%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.