CVE-2026-59851

HIGH

Libssh: libssh: authentication bypass via missing gssapi principal check

Title source: cna
STIX 2.1

Description

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.

References (3)

Core 3
Core References
Vendor Advisory vendor-advisory x_refsource_redhat
RHSA-2026:42922
https://access.redhat.com/errata/RHSA-2026:42922
Vdb Entry, X_Refsource_Redhat vdb-entry x_refsource_redhat
https://access.redhat.com/security/cve/CVE-2026-59851
Issue Tracking, X_Refsource_Redhat issue-tracking x_refsource_redhat
RHBZ#2498184
https://bugzilla.redhat.com/show_bug.cgi?id=2498184

Scores

CVSS v3 8.8
EPSS 0.0029
EPSS Percentile 20.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

CWE
CWE-863
Status published
Products (8)
libssh/libssh
Red Hat/Red Hat Enterprise Linux 10
Red Hat/Red Hat Enterprise Linux 8
Red Hat/Red Hat Enterprise Linux 9
Red Hat/Red Hat Hardened Images
Red Hat/Red Hat Hardened Images 0.12.1-4.hum1
redhat/enterprise_linux 10.0
redhat/hardened_images
Published Jul 21, 2026
Tracked Since Jul 21, 2026