CVE-2026-86060: MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2026-09-10. EPSS: 6.4% chance of exploitation in the next 30 days.

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

• MikroTik RouterOS: from 6.0, before 6.49.21 (fixed in 6.49.21); from 7.0, before 7.23.4 (fixed in 7.23.4); from 7.24, before 7.24.2 (fixed in 7.24.2)

Published 2026-09-05. Last modified 2026-09-11.