CVE-2026-89028

High

Description

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.

SeverityHigh

CVSS7.5

Exploit probability—

Product

RouterOS

PublishedSep 16, 2026

First seenSep 16, 2026

Weakness typeCWE-122CWE-122 CWE-191CWE-191

How to fix

Patches

forum.mikrotik.com/t/7-24-stable-is-released/272381

Affected products

Product	Affected versions	Fixed in
MikroTik RouterOS	v ≤ 6.49.18, 7.0.0 ≤ v ≤ 7.11.2	—

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