CVE-2026-55654: openbsd openssh Out-of-bounds Read
Vulnerability summary
CVE-2026-55654 is a low (CVSS 3.7) Out-of-bounds Read vulnerability in openbsd openssh. EPSS estimates a 0.65% chance of exploitation in the next 30 days, higher than 50.2% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 3Timeline
- 23-06-2026PublishedVulnerability first disclosed.
- 24-09-2026Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- OSV · DebianEcosystem advisory · calculated3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
- NVDNIST3.7LowCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS trend
Probability
0.65%
Chance of exploitation in the next 30 days
Percentile
50%
Versus all other CVEs
30-day change
+0.23 pp
From 0.42% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (bugzilla.redhat.com)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Debian2 products
- opensshAll versions (No fix recorded) | < 1:10.4p1-5
- openssh-gssapiAll versions (No fix recorded)
Redhat2 products
- enterprise_linuxEOL6.0 | 7.0 | 8.0 | 9.0 | 10.0
- hardened_imagesna
Ubuntu2 products
- opensshAll versions (No fix recorded)
- openssh-ssh1All versions (No fix recorded)
Openbsd1 product
- opensshna
4 vendors · 7 products
