Critical severity · published Oct 2, 2026
CVE-2026-84411
MikroTik RouterOS Integer Underflow
9.8
CVSS
0.9%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.9% · higher than 58% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
RO
RouterOS · MikroTik
before 7.24 · source: vendor
In the news
VulnerabilityCritical
MikroTik RouterOS
View CSAF Summary Successful exploitation of this vulnerability could allow an attacker to achieve remote code execution or cause a denial of service. The following versions of MikroTik RouterOS are affected: RouterOS <7.24 (CVE-2026-84411) CVSS Vendor Equipment Vulnerabilities v3 9.8 MikroTik MikroTik RouterOS Integer Underflow (Wrap or Wraparound) Background Critical Infrastructure Sectors: Communications, Information Technology Countries/Areas Deployed: Worldwide Company Headquarters Location: Latvia Vulnerabilities Expand All + CVE-2026-84411 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. View CVE Details Affected Products MikroTik RouterOS Vendor: MikroTik Product Version: MikroTik RouterOS: <7.24 Product Status: known_affected Remediations Vendor fix MikroTik recommends users update RouterOS to version 7.23 or later. The upgrade can be downloaded from the MikroTik website. https://mikrotik.com/download Relevant CWE: CWE-191 Integer Underflow (Wrap or Wraparound) Metrics CVSS Version Base Score Base Severity Vector String ...
Sep 29, 2026·CISA Advisories
Affected product
RO
RouterOS
MikroTik
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