Findings

CVE-2026-55655

A flaw was found in OpenSSH.

Published Jun 23, 2026 · updated Oct 14, 2026 · openbsd 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.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 23, 2026 · NIST NVD

    Detected

    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 inpu

  2. Oct 14, 2026 · NIST NVD

    Updated

    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 inpu

  3. Oct 14, 2026 · NIST NVD

    Updated

    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 inpu

Affected

  • cpe openbsd/opensshversion unspecified
  • cpe redhat/enterprise linux10.0
  • cpe redhat/enterprise linux6.0
  • cpe redhat/enterprise linux7.0
  • cpe redhat/enterprise linux8.0
  • cpe redhat/enterprise linux9.0

Sources

  • CVE.orgCVE-2026-55655

    Official CVE identifier

    cve.org
  • NIST NVDCVE-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 pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A suc

    nvd.nist.gov

References

CVE-2026-55655 · ZeroDay Findings