CVE-2026-55655 Other in Red Hat Enterprise Linux 10
Local attackers can hijack X11 forwarding via abstract socket pre-binding, compromising confidentiality and allowing session manipulation.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2026-55655?
CVE-2026-55655 is a medium-severity vulnerability in OpenSSH, published on 23 Jun 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
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.
Weakness: CWE-923
Which versions are affected by CVE-2026-55655?
It affects 2 products.
Products include OpenSSH, Redhat Enterprise Linux.
How do I fix CVE-2026-55655?
Apply the vendor's patch.
Is CVE-2026-55655 being exploited?
There is no known exploitation of CVE-2026-55655 in the wild and no public exploit code.
Other vulnerabilities in OpenSSH
Sources
Also known as AZL-91197, CLSA-2026-1785143860, CLSA-2026-1785153163, GHSA-wcvf-3x75-j4c6, UBUNTU-CVE-2026-55655.