CVE-2026-86060: SSH session privilege manipulation via a crafted username in Mikrotik RouterOS
In CISA’s Known Exploited Vulnerabilities catalog: MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability.
Added , federal remediation due . Known ransomware use: Unknown.
Required action: 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.
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)
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · CWE-88
Status incidents that name it
No tracked status incident names this CVE.
Affected vendors and products
Mikrotik: RouterOS
References
- CVE record on cve.org (opens in new tab)
- NVD entry (opens in new tab)
- cert.pl/en/posts/2026/09/mikrotik-routeros-cve (opens in new tab)
- cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploi… (opens in new tab)
- forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 (opens in new tab)
- forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 (opens in new tab)
- forum.mikrotik.com/t/7-24-2-stable-is-released/272800 (opens in new tab)
- mikrotik.com/supportsec/september-2026-vulnerability/ (opens in new tab)
- npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt… (opens in new tab)
- CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (opens in new tab)
- This product uses data from the NVD API but is not endorsed or certified by the NVD. (opens in new tab)
- Known Exploited Vulnerabilities catalog from CISA. (opens in new tab)
- EPSS scores from FIRST (Exploit Prediction Scoring System). (opens in new tab)