CVE-2026-59849: Libssh

High severity, CVSS 7.5. EPSS: 0.4% chance of exploitation in the next 30 days.

A flaw was found in libssh. Logic errors in automatic certificate-based public key authentication can cause libssh clients to loop indefinitely when configured certificates are missing or repeatedly rejected by a server, leading to denial of service.

Affected products

• Libssh Libssh: from 0.11.0, before 0.11.5 (fixed in 0.11.5); version 0.12.0 only
• Red Hat Enterprise Linux: version 10.0 only; version 10.2 only
• Red Hat Enterprise Linux For Els: version 10.2 only
• Red Hat Enterprise Linux For Eus: version 10.2 only
• Red Hat Enterprise Linux For IBM Z Systems: version 10.0 only; version 10.2 only
• Red Hat Enterprise Linux For IBM Z Systems Els: version 10.2 only
• Red Hat Enterprise Linux For IBM Z Systems Eus: version 10.2 only
• Red Hat Enterprise Linux For Power Little Endian: version 10.0 only; version 10.2 only
• Red Hat Enterprise Linux For Power Little Endian Els: version 10.2 only
• Red Hat Enterprise Linux For Power Little Endian Eus: version 10.2 only
• Red Hat Hardened Images: affected versions not specified

Published 2026-07-21. Last modified 2026-09-22.