Buffer overflow in Mikrotik Routeros
CVE-2026-89028
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.
Vulnerability class: Buffer Overflow
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
Affected products
Weakness classification (CWE)
References
- disclosure@vulncheck.com (vendor-advisory, patch)
- disclosure@vulncheck.com (third-party-advisory)
Frequently asked questions
- What is CVE-2026-89028?
- CVE-2026-89028 is a high-severity vulnerability in Mikrotik Routeros, classified under Heap-based Buffer Overflow. CVSS score: 7.5/10. Published 2026-09-16.
- How severe is CVE-2026-89028?
- High severity. CVSS v3 base score is 7.5 out of 10.