CVE-2026-59851 PUBLISHED

Libssh: libssh: authentication bypass via missing gssapi principal check

Assigner: redhat
Reserved: 07.07.2026 Published: 21.07.2026 Updated: 21.07.2026

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.

Metrics

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

Product Status

Vendor Red Hat
Product Red Hat Enterprise Linux 10
Versions Default: affected
Vendor Red Hat
Product Red Hat Enterprise Linux 8
Versions Default: unaffected
Vendor Red Hat
Product Red Hat Enterprise Linux 9
Versions Default: unaffected
Vendor Red Hat
Product Red Hat Hardened Images
Versions Default: affected

Workarounds

Disable GSSAPIKeyExchange.

Credits

  • Red Hat would like to thank Aisle Research for reporting this issue.

References

Problem Types

  • Incorrect Authorization CWE