CVE-2026-86060
SSH session privilege manipulation via a crafted username in Mikrotik RouterOS
- State
- Published
- Severity
- 9.2 Critical
- Published
- Sep 5, 2026
- Updated
- Sep 11, 2026
- Reserved
- Sep 4, 2026
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)
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 9.2 Critical | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | CERT-PL |
Weaknesses
- CWE-88 Improper neutralization of argument delimiters in a command ('argument injection')
Affected Products
| Product | Versions |
|---|---|
RouterOSMikrotik |
|
References
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cvethird-party-advisory
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/technical-description
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/exploit
- https://mikrotik.com/supportsec/september-2026-vulnerability/vendor-advisory
- https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802release-notes
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801release-notes
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800release-notes
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-86060government-resource
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