CVE catalog

CVE-2026-55655

Severity: Medium · CVSS 6.1CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N
Published: Jun 22, 2026, 10:00:00 PM UTC
Source: [NVD] · [CVE record]
EPSS: 0.10% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	openssh	sid	`1:10.6p1-1`	not affected
Debian	openssh	forky	`1:10.6p1-1`	not affected
Debian	openssh	trixie	`1:10.0p1-7+deb13u4`	not affected
Debian	openssh	trixie-security	`1:10.0p1-7+deb13u2`	not affected
Debian	openssh	bookworm	`1:9.2p1-2+deb12u10`	not affected
Debian	openssh	bookworm-security	`1:9.2p1-2+deb12u9`	not affected
Cpe	openssh	Not reported	Not reported	vulnerable
Cpe	openssh	Not reported	Not reported	unknown
Cpe	enterprise_linux	Not reported	Not reported	unknown
Cpe	openssh	Not reported	Not reported	unknown
Cpe	enterprise_linux	Not reported	Not reported	unknown

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	openssh	source	sid	`Not affected`	unimportant	Not reported	Not reported
Debian	openssh	source	forky	`Not affected`	unimportant	Not reported	Not reported
Debian	openssh	source	trixie	`Not affected`	unimportant	Not reported	Not reported
Debian	openssh	source	bookworm	`Not affected`	unimportant	Not reported	Not reported

OpenFactory catalog packages

[Debian 12 (Bookworm)]

[openssh-client]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · amd64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · arm64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · amd64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · arm64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · amd64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · arm64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · amd64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · arm64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
[openssh-client-gssapi]Not affected
Source package: [openssh]
Details (2)
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
[openssh-server]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · amd64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · arm64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · amd64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · arm64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · amd64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · arm64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · amd64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · arm64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
[openssh-server-gssapi]Not affected
Source package: [openssh]
Details (2)
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
[openssh-sftp-server]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · amd64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · arm64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · amd64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · arm64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · amd64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · arm64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · amd64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · arm64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
[openssh-tests]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · amd64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · arm64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · amd64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · arm64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · amd64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · arm64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · amd64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · arm64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
[ssh]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · all · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · all · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · all · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · all · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · all · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · all · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · all · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
[ssh-askpass-gnome]Not affected
Source package: [openssh]
Details (8)
- 1:9.2p1-2+deb12u10 · amd64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u10 · arm64 · bookworm
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · amd64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:10.0p1-7~bpo12+1 · arm64 · bookworm-backports
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · amd64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u9 · arm64 · bookworm-security
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · amd64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm
- 1:9.2p1-2+deb12u7 · arm64 · bookworm-updates
  Not affected
  nvd · openssh · debian · bookworm

Observed: Oct 27, 2026, 7:14:04 AM UTC

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]