---
id: CVE-2026-89028
title: >-
  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 ha…
summary: >-
  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 ha…
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-122
  - CWE-191
vendor: MikroTik
product: RouterOS
affected:
  - RouterOS <= 6.49.18
  - RouterOS >= 7.0.0 <= 7.11.2
published: '2026-09-16'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T20:18:52.157'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89028'
references:
  - url: 'https://forum.mikrotik.com/t/7-24-stable-is-released/272381'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/mikrotik-routeros-heap-corruption-via-smb1-sessionsetupandx
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-17T19:16:36.762410Z'
ingestedAt: '2026-09-16T13:56:12.618Z'
epss: 0.00557
epssPercentile: 0.45011
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.