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

Exp

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.

Published: 2026-06-23 Last update: 2026-07-08 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-55654 is rated Exploit Available (50/100): CVSS Low severity, with low exploitation likelihood (EPSS 0.37%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-55654

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-55654

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-07-09 0.33% 0.37% +0.03%
2 2026-06-23 — 0.33% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-55654

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
3.7 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 2.2 1.4 [email protected]

Weakness enumeration for CVE-2026-55654

GitHub Security Advisory for CVE-2026-55654

GHSA-5mx2-7g4j-9m39 · Severity: low — A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the...

OS Trackers for CVE-2026-55654

vendor priority summary link
debian not yet assigned CVE-2026-55654 not yet assigned priority: Debian including 1 source packages (openssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): undetermined 5. https://security-tracker.debian.org/tracker/CVE-2026-55654
redhat low — https://access.redhat.com/security/cve/CVE-2026-55654
ubuntu low CVE-2026-55654 low priority: Ubuntu including 2 source packages (openssh, openssh-ssh1), 16 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): deferred 8, ignored 7, needs-triage 1. https://ubuntu.com/security/CVE-2026-55654

Affected software / configurations for CVE-2026-55654

Vendor Product Version Raw CPE
openbsd openssh — cpe:2.3:a:openbsd:openssh:-:*:*:*:*:*:*:*
redhat hardened_images — cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*
redhat enterprise_linux 6.0 cpe:2.3:o:redhat:enterprise_linux:6.0:*:*:*:*:*:*:*
redhat enterprise_linux 7.0 cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
redhat enterprise_linux 10.0 cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*

References for CVE-2026-55654

cvelogic Threat Intelligence