CVE-2026-89028: MikroTik RouterOS

High severity, CVSS 7.5. EPSS: 0.6% chance of exploitation in the next 30 days.

MikroTik RouterOS before 7.24 contains a heap memory corruption vulnerability in the userspace SMB daemon that allows remote attackers to corrupt adjacent heap memory by supplying a crafted uniPwdLen value in the SMB1 SessionSetupAndX handler. An attacker can send a malformed SMB1 request with a uniPwdLen field that triggers an integer underflow, causing the resulting value to be used as the copy length in a memory copy operation into a smaller heap buffer, corrupting adjacent heap memory.

Affected products

• MikroTik RouterOS: up to and including 6.49.18; from 7.0.0, up to and including 7.11.2

Published 2026-09-16. Last modified 2026-09-24.