Advisory severityHigh8.8Red Hat Linux

High [CVE-2026-59851] authentication bypass via missing GSSAPI principal check

This high-severity Red Hat Linux advisory covers CVE-2026-59851 affecting Red Hat Enterprise Linux 10, Red Hat Hardened Images, Red Hat package: libssh.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-59851 Source published Jul 21, 2026Source updated Jul 21, 2026

VulniPulse record published Jul 21, 2026Record updated Aug 11, 2026

CVE-2026-59851

Affected products & platforms

Red Hat LinuxRed Hat Enterprise Linux

Open source advisory

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Summary

A flaw was found in libssh. On servers with GSSAPIKeyExchange enabled, the gssapi-keyex path does not verify whether the authenticated Kerberos principal is authorized for the requested local user, allowing authenticated clients to log in as arbitrary users.

Red Hat severity: Important — CVSS 8.8 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). Weakness: CWE-863.

Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Hardened Images. Red Hat lists Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9 as not affected.

Red Hat fixing advisory: RHSA-2026:55855, RHSA-2026:42922.

Affected products named by the advisory: Red Hat package: libssh.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.

Official advisory · high-confidence parse· fetched 16 days ago·verify at source

Fixed versions

libssh-0:0.12.0-3.el10_2
libssh-main-0.12.1-4.hum1
RHSA-2026:55855
RHSA-2026:42922

Official advisory · high-confidence parse· fetched 16 days ago·verify at source

Mitigation checklist

Recommended fix / mitigation

Disable GSSAPIKeyExchange.

Official advisory · high-confidence parse· fetched 16 days ago·verify at source

Sources

Official and corroborating records used to build this advisory.

Red Hat Security Data APIofficial
Official vendor source used to discover this advisory; it remains the authority for affected products and remediation. Discovered from the machine-readable feed https://access.redhat.com/hydra/rest/securitydata/cve.json; this link opens the Red Hat Linux advisory index instead of the raw feed document.
Red Hat Linux
Official vendor advisoryofficial
Official advisory page fetched and parsed; accepted detail fields are attributed to this page.
Red Hat Linux
CVE.org CNA affected-product recordCVE.org
Structured CNA affected[] data independently confirmed the affected product scope; native advisory content remains authoritative.
CVE Program

Cross-references

Validate CVE metadata against the authoritative registries.

CVE-2026-59851NVD CVE.org MITRE

Discussion(0)

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