CVE-2026-59851

libssh: libssh: authentication bypass via missing GSSAPI principal check

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Severity

Important

Red Hat Product Security

8.8

CVSS 3.1

Review impact separately from score.

Published · July 21, 2026

Updated · August 18, 2026

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.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Disable GSSAPIKeyExchange.

CVSS / CWE

CVSS 3.1 · 8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CWE-863 · Incorrect Authorization