RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request. On affected builds the server dispatches the command, enabling unauthenticated creation, overwrite, and reconstruction of files in the RouterOS managed file namespace, including support files containing configuration and diagnostic data.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
Medium 6.5Actively exploited
CVE-2026-67279
MikroTik RouterOS — Improper Enforcement of Behavioral Workflow.
RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request.
WeaknessCWE-841
Published Updated Source NVD and CISA KEV
CVSS 3.1
6.5
AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N
Exploit chance, 30 days
2.3%
Higher than 83% of all CVEs (EPSS)
Status
Actively exploited
On CISA KEV since 25 Sep 2026
Patch
Unknown
Check the vendor advisory
What happened
What to do
- 01Check whether you run MikroTik RouterOS, and which version.
- 02Follow the vendor advisory for a fix or a workaround.
- 03Apply 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.
CISA deadlineUS federal agencies must remediate by
References
Timeline · UTC
- Published to NVD
- Added to CISA KEV
- NVD record updated
- CISA remediation deadline
Also actively exploited
Other CVEs in MikroTik RouterOS
3 more CVEs, 2 actively exploited