CVE-2026-86060
Mikrotik RouterOS
Summary
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 requir…
Published: 2026-09-05 · In KEV since: 2026-09-10
Analysis
🔴 Critical — actively exploited
Weakness: CWE-88.
How it's exploited: Exploitable over the network (internet-reachable), unauthenticated, no user interaction, and with low complexity.
⚠️ Critical combo: remote, unauthenticated and no interaction → trivial to automate.
Impact: Full compromise (confidentiality, integrity and availability).
Status: Active exploitation confirmed by CISA (KEV).
- Patch now: it is in CISA's actively-exploited catalog (KEV), with a deadline.
- Reduce exposure: keep it off the internet; firewall, VPN or network segmentation.
- Detect: turn this CVE into detection rules.
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
The vector encodes how it's exploited (translated above, in the analysis). Break it down in the CVSS tool →
Sources: CISA KEV · EPSS · FIRST.org · NVD. Analysis derived from the CVSS vector and exploitation status (no AI). Informational; always verify against the vendor's official advisory.