---
title: "CVE-2026-89028: MikroTik RouterOS - Heap Memory Corruption"
description: "MikroTik RouterOS < 7.24 contains a heap memory corruption vulnerability caused by an integer underflow in the SMB1 SessionSetupAndX handler's uniPwdLen field, letting remote attackers corrupt adjacent heap memory, exploit requires crafted SMB1 request."
url: https://panop.io/threat-heartbeat/CVE-2026-89028/
---

# CVE-2026-89028 MikroTik RouterOS - Heap Memory Corruption

MikroTik RouterOS < 7.24 contains a heap memory corruption vulnerability caused by an integer underflow in the SMB1 SessionSetupAndX handler's uniPwdLen field, letting remote attackers corrupt adjacent heap memory, exploit requires crafted SMB1 request.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.58% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89028)

## Details

Type

Heap Memory Corruption

Impact

Denial Of Service, Remote Code Execution

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Published

16 September 2026

Updated

15 October 2026

Weakness

[CWE-122](https://cwe.mitre.org/data/definitions/122.html)

## Vendor fix

Update to version 7.24 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-89028](https://nvd.nist.gov/vuln/detail/CVE-2026-89028)
- [https://forum.mikrotik.com/t/7-24-stable-is-released/272381](https://forum.mikrotik.com/t/7-24-stable-is-released/272381)
- [https://www.vulncheck.com/advisories/mikrotik-routeros-heap-corruption-via-smb1-sessionsetupandx](https://www.vulncheck.com/advisories/mikrotik-routeros-heap-corruption-via-smb1-sessionsetupandx)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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