Description
RouterOS does not compare the complete RSA public key when matching an SSH authentication request to an authorized user key, checking the key type and modulus but omitting the exponent. Because signature verification uses the client-supplied key, an attacker knowing an authorized RSA modulus can supply a key with exponent one, forge a valid signature, and open an SSH command channel as the target user without the private key.This issue affects only 7.x branch was fixed in versions: 7.23.4 (Long-term) and 7.24.2 (Stable)
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
High
Attack Requirements
None
Privileges Required
None
User Interaction
None
Confidentiality (Vulnerable System)
High
Integrity (Vulnerable System)
High
Availability (Vulnerable System)
High
Confidentiality (Subsequent System)
None
Integrity (Subsequent System)
None
Availability (Subsequent System)
None
Affected products
- MikroTik / RouterOS7.24 – 7.24.2
- MikroTik / RouterOS7.0.0 – 7.23.4
- MikroTik / RouterOS6.0.0 – 6.49.21
- MikroTik / RouterOS7.9 – 7.23.4
References
- MISChttps://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
- MISChttps://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
- MISChttps://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
- MISChttps://mikrotik.com/supportsec/september-2026-vulnerability/
- MISChttps://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
- MISChttps://forum.mikrotik.com/t/7-24-2-stable-is-released/272800
Updated 7m ago · 8 sources