CVE-2026-55654 — Openssh: heap out-of-bounds read in red hat enterprise linux versions of openssh gssapi indicator cleanup due to missing null sentinel termination

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

1. Identify exposed assets running the affected vendor/product/version combinations (Openbsd Openssh, Red Hat Enterprise Linux, Red Hat Hardened Images…).
2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
3. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
4. Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-125 · Out-of-bounds Read

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.65%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

• Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
• Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · red hat/red hat enterprise linux 10, red hat/red hat enterprise linux 9, red hat/red hat hardened images, red hat/red ha
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• SSVC assessment updated
  Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
• Record published
  Oct 13, 2026
• CVSS changed · 3.7
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• CVE published
  Jun 23, 2026 · redhat

Source activity

Repeated readings are counted rather than listed.

• 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

7 on the record

• bugzilla.redhat.com/show_bug.cgi
  Exploit, Issue Tracking, Vendor Advisory, issue-tracking, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/security/cve/CVE-2026-55654
  Vendor Advisory, vdb-entry, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2026:47756
  vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2026:54387
  vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2026:47757
  vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2026:58981
  vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database
• access.redhat.com/errata/RHSA-2026:36759
  vendor-advisory, x_refsource_REDHAT, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-92982 Ansible-operator-plugins: ansible operator plugins: arbitrary code execution via jinja2 template injection 5h
• Medium CVE-2026-110927 Openssh: openssh: a compressed payload can expand past the maximum packet size 8h
• Medium CVE-2026-110924 Openssh: openssh: gssapi delegated credentials can be stored after a failed authentication 8h
• Medium CVE-2026-110926 Openssh: openssh: shared lz77 compression dictionary leaks plaintext across channels 16h
• Medium CVE-2026-110925 Openssh: openssh: '$' and '\' in a command-line username expand through %u 16h
• Medium CVE-2026-110923 Openssh: openssh: sftp can write outside the destination directory from a server-supplied path 16h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

• No fixed version, patch or mitigation documented.
• No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
• No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
• No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-55654 is "Openssh: heap out-of-bounds read in red hat enterprise linux versions of openssh gssapi indicator cleanup due to missing null sentinel termination", rated Low. It affects Openssh (Openbsd); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 3.7 describes technical severity. EPSS 0.65% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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