CVE-2026-55655
published 2026-06-23CVE-2026-55655: 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…
PriorityP426medium6.1CVSS 3.1
AVLACLPRNUIRSUCHILAN
EPSS
0.09%
0.6th percentile
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
5 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
| redhat | enterprise_linux | — | — |
CVSS provenance
nvdv3.16.1MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
vendor_redhat5.0MEDIUM
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GHSA
A flaw was found in OpenSSH.
ghsa_unreviewed·2026-06-23
CVE-2026-55655 [MEDIUM] CWE-923 A flaw was found in OpenSSH.
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.
Red Hat
openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in Red Hat Enterprise Linux OpenSSH client versions
vendor_redhat·2026-06-22·CVSS 5.0
CVE-2026-55655 [MEDIUM] CWE-923 openssh: Local MITM of X11 forwarding via abstract UNIX socket pre-binding in Red Hat Enterprise Linux OpenSSH client versions
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.
Statement: This is a Moderate severity flaw. The OpenSSH client in Red Hat Enterprise Linux is vulnerable to a local man-in-the-middle attack on X11 forwarding connections. Exploitation requires an attacker to
No detection rules found.
No public exploits indexed.
2026-06-23
Published