Auth bypass in Libssh
CVE-2026-59851
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.
Vulnerability class: Broken Access Control
EPSS: 0.003 (21.2th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
Affected products
- Libssh
- Red Hat Enterprise Linux 10 — versions 0:0.12.0-3.el10_2
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat Hardened Images — versions 0.12.1-4.hum1
- Redhat Enterprise_linux — versions 10.0
- Redhat Hardened_images
Weakness classification (CWE)
References
- secalert@redhat.com (x_refsource_REDHAT, vdb-entry, Vendor Advisory)
- secalert@redhat.com (x_refsource_REDHAT, issue-tracking, Issue Tracking, Vendor Advisory)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory, Issue Tracking)
- secalert@redhat.com (x_refsource_REDHAT, vendor-advisory)
Frequently asked questions
- What is CVE-2026-59851?
- CVE-2026-59851 is a high-severity vulnerability in Libssh, classified under Incorrect Authorization. CVSS score: 8.8/10. Published 2026-07-21.
- How severe is CVE-2026-59851?
- High severity. CVSS v3 base score is 8.8 out of 10.