CVE-2026-59849 PUBLISHED

Libssh: libssh: denial of service via automatic certificate authentication loop

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

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.

Metrics

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

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

Do not connect to untrusted SSH servers and do not use certificates until patched.

Credits

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

References

Problem Types

  • Loop with Unreachable Exit Condition ('Infinite Loop') CWE