---
id: CVE-2026-84411
title: >-
  The web management service in affected RouterOS versions contains an integer
  underflow in its HTTP request body handling that is reachable before
  authentication
summary: >-
  The web management service in affected RouterOS versions contains an integer
  underflow in its HTTP request body handling that is reachable before
  authentication. This can be leveraged by an unauthenticated network attacker
  to achieve arb…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-191
vendor: MikroTik
product: RouterOS
affected:
  - RouterOS < 7.24
published: '2026-10-02'
updated: '2026-10-02'
sourceUpdated: '2026-10-02T23:16:58.417'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-84411'
references:
  - url: >-
      https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-272-06.json
    label: ics-cert@hq.dhs.gov
  - url: 'https://mikrotik.com/download'
    label: ics-cert@hq.dhs.gov
  - url: 'https://www.cisa.gov/news-events/ics-advisories/icsa-26-272-06'
    label: ics-cert@hq.dhs.gov
tags:
  - nvd
  - cve.org
ingestedAt: '2026-10-02T22:33:09.860Z'
---

## Overview

The web management service in affected RouterOS versions contains an integer underflow in its HTTP request body handling that is reachable before authentication. This can be leveraged by an unauthenticated network attacker to achieve arbitrary code execution as root, or to cause a denial of service, using a single crafted request.

## Remediation

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