Authentication vulnerability affecting Mikrotik RouterOS

Mikrotik RouterOS is a Linux-based operating system developed by Mikrotik for its routers and other network equipment, providing functionality for routing, firewalls, wireless network management, and more. This product is affected by a vulnerability labeled CVE-2026-67276 which results from a defect in the comparison of RSA public keys during SSH authentication requests. The system checks the key type and module, but omits the exponent. Exploitation of this vulnerability would allow an unauthenticated attacker, knowing the RSA module of an authorized key, to provide a key with an exponent one. He could thus forge a valid signature and open an SSH command channel as the targeted user, without having the private key. It is classified high, with a severity score of 8.1 according to CVSS v3.1.

• Mikrotik RouterOS 6.49.x versions prior to 6.49.21;
• Mikrotik RouterOS 7.23.x versions prior to 7.23;
• Mikrotik RouterOS 7.24.x versions prior to 7.24.2;

RECOMMENDED ACTIONS:

• Update Mikrotik RouterOS to versions 6.49.21, 7.23.4, 7.24.2 or later;