CVE-2026-86060 CRITICAL

CVE-2026-86060: SSH session privilege manipulation via a crafted username in Mikrotik RouterOS

Vendor Mikrotik
Product RouterOS
Weakness CWE-88
KEV Status Known Exploited
Published September 5, 2026
Last update September 11, 2026
View on NVD All CVEs

CVSS base score

9.2/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

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

What the vulnerability does

01Description

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 mandated remediation

02CISA 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.

Key dates

03Disclosure timeline

September 5, 2026 CVE published
September 11, 2026 Record updated

External resources

04References

NVD — National Vulnerability Database https://nvd.nist.gov/vuln/detail/CVE-2026-86060 CWE — Common Weakness Enumeration https://cwe.mitre.org/data/definitions/88.html AskarLabs — CWE-88 write-up Argument Injection CISA KEV Reference https://mikrotik.com/supportsec/september-2026-vulnerability CISA KEV Reference https://www.cisa.gov/news-events/directives/bod-26-04-prioriti… CISA KEV Reference https://www.cisa.gov/news-events/directives/bod-26-04-implemen… CISA KEV Reference https://nvd.nist.gov/vuln/detail/CVE-2026-86060