CVE-2026-86060
KEVMikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability
Description
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.
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)
CVSS 4.0 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XPublishedSep 5, 2026
Last modifiedSep 11, 2026
Added to KEVSep 10, 2026
Remediation dueSep 13, 2026
References
- cert.pl/en/posts/2026/09/mikrotik-routeros-cveThird Party Advisory
- cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/MitigationThird Party Advisory
- forum.mikrotik.com/t/6-49-21-long-term-is-released/272802Release Notes
- forum.mikrotik.com/t/7-23-4-long-term-is-released/272801Release Notes
- forum.mikrotik.com/t/7-24-2-stable-is-released/272800Release Notes
- mikrotik.com/supportsec/september-2026-vulnerability/Vendor Advisory
- npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ExploitThird Party Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-86060US Government Resource
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Risk assessment · High
Actively exploited. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 44 days
- CVSS
- 9.2 CRITICAL
- EPSS (30-day exploit probability)
- 6.4% · top 6% of all CVEs
- Weakness
- CWE-88
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.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.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.