CVE-2015-5600: OpenBSD OpenSSH

High severity, CVSS 8.1. EPSS: 9.4% chance of exploitation in the next 30 days.

The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.

Affected products

• OpenBSD OpenSSH: up to and including 6.9

Published 2015-08-03. Last modified 2026-06-17.