High · published September 6, 2026
CVSS calls it high at 8.2. It is confirmed in active exploitation. It sits in the 75.1th percentile for exploit probability.
RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel.
This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
| Product | Versions | Fixed in |
|---|---|---|
| mikrotik/routeros | ≥ 6.0, < 6.49.21 | 6.49.21 |
| mikrotik/routeros | ≥ 7.0, < 7.23.4 | 7.23.4 |
| mikrotik/routeros | ≥ 7.24, < 7.24.2 | 7.24.2 |