What is CVE-2026-84411?

CVE-2026-84411 is a critical-severity vulnerability in Mikrotik Routeros, classified under Integer Underflow. CVSS score: 9.8/10. Published 2026-10-02.

How severe is CVE-2026-84411?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Integer overflow in Mikrotik Routeros

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.

Published 2026-10-02.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.

Affected products

Mikrotik Routeros

Weakness classification (CWE)

CWE-191 — Integer Underflow

References

Frequently asked questions

What is CVE-2026-84411?: CVE-2026-84411 is a critical-severity vulnerability in Mikrotik Routeros, classified under Integer Underflow. CVSS score: 9.8/10. Published 2026-10-02.
How severe is CVE-2026-84411?: Critical severity. CVSS v3 base score is 9.8 out of 10.