11 September 2026
Reference: CVE-2026-67277
1. What is being reported?
The MikroTik RouterOS software has a flaw where it accepts certain network test connections before the user has logged in properly. This allows an attacker to send special data that can cause the router to crash or behave unpredictably. This problem affects specific versions of the software and has been fixed in recent updates.
2. What this means in plain English
If your organisation uses a MikroTik router with the affected software, hackers could potentially disrupt your internet connection or gain control of your router without needing to log in. This could lead to loss of internet access or exposure of your network to further attacks.
3. Could this affect a small business?
Small businesses, charities, clubs, or any organisation using MikroTik routers with the affected software versions could be at risk. If you do not use MikroTik routers, or your devices have been updated to the fixed versions, you are likely not affected.
4. What to do now
- Check if your MikroTik router is running an affected version of RouterOS.
- If it is, arrange to update the router software to the fixed versions: 6.49.21, 7.23.4, or 7.24.2 as soon as possible.
- If you cannot update immediately, ask your IT provider about temporary mitigations to reduce risk.
- Review your router’s exposure to the internet and limit access where possible.
5. Ask your IT provider
Can you confirm if our MikroTik routers are running vulnerable versions of RouterOS and have they been updated to the latest fixed versions?
6. Bottom line
Update your MikroTik router software promptly to protect your organisation from an actively exploited security flaw.
Information sourced from CISA KEV, NVD and reputable security reporting.