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
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-84411
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-84411
mikrotik.com
https://mikrotik.com/download
www.cisa.gov
https://www.cisa.gov/news-events/ics-advisories/icsa-26-272-06
github.com
https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-272-06.json
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