Is CVE-2026-55655 in the CISA KEV catalog?

No. CVE-2026-55655 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-55655?

CVE-2026-55655 has a CVSS v3 base score of 5.0 (Moderate).

What is the EPSS score for CVE-2026-55655?

CVE-2026-55655 has an EPSS score of 0.08% (0th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix or mitigate CVE-2026-55655?

No published fix for CVE-2026-55655 has been found yet. Check the linked vendor advisories for guidance as it becomes available.

CVE & CISA-KEV Catalog

CVE-2026-55655

MEDIUM

5.0

CVSS v3

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.

CWE-923

How to fix

No published remediation has been found for this vulnerability's affected products yet.

Mitigation guidance may be in the linked vendor advisories in the References section below.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityHigh

Privileges RequiredLow

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityLow

AvailabilityNone

CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:U/C:H/I:L/A:N

Exploit Intelligence

0.08%probability of exploitation in 30 days

0thpercentile

Low risk: more likely to be exploited than 0% of all known CVEs.

References

Vendor Advisory2

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-06-25.