CVE-2026-84411 RouterOS - Remote Code Execution & Denial of Service

RouterOS contains an integer underflow in HTTP request body handling, letting unauthenticated network attackers achieve remote code execution as root or cause denial of service using a crafted request.

CVSS base score 9.8 /10
Critical
CISA KEV
Not listed
Public exploit
Proof of concept available
Authentication
Not required
EPSS
0.95% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Remote Code Execution
Impact
Remote Code Execution, Denial Of Service
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2 October 2026
Updated
15 October 2026
Weakness
CWE-191

Vendor fix

Update to the latest RouterOS version.

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

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