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)
Affected products
Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.
Mikrotik RouterOS
Default version status: unaffected
7.24 to < 7.24.2affected7.0.0 to < 7.23.4affected6.0.0 to < 6.49.21affected
References
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve ↗
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ ↗
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ ↗
- https://mikrotik.com/supportsec/september-2026-vulnerability/ ↗
- https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 ↗
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 ↗
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 ↗
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-86060 ↗