All vulnerabilities
CVE-2026-84411

MikroTik RouterOS Integer Underflow

MikroTik RouterOSNetwork & edge
Open in ThreatlineRecord JSON
CVSS
9.8Critical
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.95%Chance of exploitation activity in the next 30 days, higher than 60% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in7.24Fixed versionCVE List
Published2 Oct 2026Updated 3 Oct 2026CVE List

What fixes it

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 2

  • RouterOSaffected: all versions before 7.24CVE List
  • RouterOSunaffected: 7.24CVE List

References 3