CVE-2026-55655
Low
No strong exploitation signal.
CVSS base
5.0
MEDIUM
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N
EPSS — probability of exploitation (30 days)
0.1%
0.4th percentile
CISA KEV
Not listed
Weakness / dates
CWE-923
Published 2026-06-23 · modified 2026-09-01
CVSS breakdown
CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N
| Attack Vector | L | Local |
| Attack Complexity | H | High |
| Privileges Required | L | Low |
| User Interaction | R | Required |
| Scope | U | Unchanged |
| Confidentiality | H | High |
| Integrity | L | Low |
| Availability | N | None |
Timeline
- 2026-06-23 — Published (NVD)
- 2026-09-01 — Last modified (NVD)
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.
Affected
References
- https://access.redhat.com/errata/RHSA-2026:36759
- https://access.redhat.com/errata/RHSA-2026:47755
- https://access.redhat.com/errata/RHSA-2026:47756
- https://access.redhat.com/errata/RHSA-2026:47757
- https://access.redhat.com/errata/RHSA-2026:54387
- https://access.redhat.com/errata/RHSA-2026:58981
- https://access.redhat.com/security/cve/CVE-2026-55655
- https://bugzilla.redhat.com/show_bug.cgi?id=2462250