MikroTik · RouterOS
CVE-2026-86060
SSH session privilege manipulation via a crafted username in Mikrotik RouterOS
What it is
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)
CISA: MikroTik RouterOS contains an improper neutralization of argument delimiters in a command vulnerability which allows an attacker to change the trusted RouterOS policy mask, leading to privilege escalation.
What to do
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
Deadline for US federal agencies: September 13, 2026
- Added to the CISA list
- September 10, 2026
- Published
- September 5, 2026
- Severity
- Critical 9.2 CVSS 4.0
- Chance of attacks in the next 30 days (EPSS)
- 6.4% in the top 6.4% of all known vulnerabilities
- Weakness
- CWE-88
- More details
- NVD · CVE.org · CISA
All references (7)
- https://mikrotik.com/supportsec/september-2026-vulnerability/
- 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://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
More exploited flaws from MikroTik
| Added | Vulnerability | Product | Severity | Attack chance |
|---|---|---|---|---|
| Sep 25, 2026 | Improper Enforcement of Behavioral Workflow | RouterOS | Medium 6.9 | 2.3% |
| Sep 10, 2026 | Missing Authentication for Critical Function | RouterOS | High 8.8 | 1.6% |
| Sep 8, 2022 | Stack-Based Buffer Overflow | RouterOS | Critical 9.8 | 66% |
| Dec 1, 2021 | Router OS Directory Traversal | RouterOS | Critical 9.1 | 96% |
Sources: Known Exploited Vulnerabilities (CISA, public domain), CVE records (cve.org) and EPSS (FIRST). The chance of attacks is the EPSS estimate that someone will try to exploit the flaw in the next 30 days.