Description
RouterOS contains an argument-handling flaw in the SSH login path involving usernames that begin with a prohibited character, allowing for the trusted RouterOS policy mask to be changed, leading to privilege escalation. Exploitation requires an unauthenticated SSH session to reach the RouterOS login helper.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
CVSS breakdown
CVSS 4.0
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
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
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Affected products
- MikroTik / RouterOS7.24 – 7.24.2
- MikroTik / RouterOS7.0.0 – 7.23.4
- MikroTik / RouterOS6.0.0 – 6.49.21
- MikroTik / RouterOS6.0 – 6.49.21
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/6-49-21-long-term-is-released/272802
- 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 9m ago · 8 sources