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
- Is it exploited?
Not on CISA's list. CISA has not added it to the Known Exploited Vulnerabilities catalog as of . If CISA adds it, this page shows it as known exploited.
- How likely is exploitation in the next 30 days?
- 0.7%
EPSS score, percentile 51.2 of all scored records. A probability estimated by FIRST, not a report of exploitation.
- How severe?
- 3.7 Low
CVSS v3.1 base score, given by the CNA
- What should I do?
CISA has set no required action, because the vulnerability is not in KEV.
- Which versions are affected?
Unaffected 0:9.9p1-25.el10_2; 0:9.9p1-9.el9_8; 0:9.9p1-9.el9_8; 10.3p1-6.hum1; 1786435483; 1786533529; and 2 more
Source: CISA KEV 2026.10.29, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.
What to do
Advisories and patches
This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.
Affected products and versions
As listed in the CVE record.
| Status | Versions |
|---|---|
| Unaffected | 0:9.9p1-25.el10_2 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 0:9.9p1-9.el9_8 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 0:9.9p1-9.el9_8 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 10.3p1-6.hum1 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 1786435483 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 1786533529 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 1787135742 |
Versions not listed are: affected.
| Status | Versions |
|---|---|
| Unaffected | 1787241260 |
Versions not listed are: affected.
| Status | Versions |
|---|
Versions not listed are: unaffected.
| Status | Versions |
|---|
Versions not listed are: unaffected.
| Status | Versions |
|---|
Versions not listed are: unaffected.
| Status | Versions |
|---|
Versions not listed are: affected.
| Status | Versions |
|---|
Versions not listed are: affected.
Versions the record lists as unaffected: 0:9.9p1-25.el10_2, 0:9.9p1-9.el9_8, 10.3p1-6.hum1, 1786435483, 1786533529, 1787135742, 1787241260.
Source: CVE List, as of . About the data.
About this vulnerability
A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the…
Summary: CVE record, as of .
- CISA has not added CVE-2026-55654 to its Known Exploited Vulnerabilities (KEV) catalog, as of 29 Oct 2026.
- The CVE record was published on 23 Jun 2026.
- The CVE record carries a CVSS v3.1 base score of 3.7 (Low), given by its CNA.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 0.7% (percentile 51.2), as of 29 Oct 2026. EPSS is a statistical estimate, not a report of exploitation.
- CISA's SSVC assessment in the CVE record: exploitation none, automatable no, technical impact partial.
- The credits in the CVE record name AISLE as finder.
Source: CISA KEV 2026.10.29, as of ; CVE List, as of ; FIRST EPSS, as of . About the data.
Description
Openssh: heap out-of-bounds read in red hat enterprise linux versions of openssh gssapi indicator cleanup due to missing null sentinel termination
A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.
Source: CVE List, as of . About the data.
Weakness
CWE-125
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| CVE record last updated |
References
2
Known exploited Red Hat vulnerabilities
- CVE-2015-3246: Red Hat Libuser Race Condition Vulnerability
- CVE-2015-5287: Red Hat Automatic Bug Reporting Tool Privilege Escalation Vulnerability
- CVE-2018-14667: Red Hat JBoss RichFaces Framework Expression Language Injection Vulnerability
- CVE-2021-3560: Red Hat Polkit Incorrect Authorization Vulnerability
- CVE-2021-4034: Red Hat Polkit Out-of-Bounds Read and Write Vulnerability