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UK Cyber Defence
VulnerabilityAwaiting Analysis

CVE-2026-84411

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.

CRITICAL 9.3EPSS 0.86%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.86%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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 4.0
9.3 CRITICALCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/M
EPSS
0.86% probability · 58th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-191
Source
ics-cert@hq.dhs.gov
EPSS trend
0%3%5%3 October 2026: 0.95%26 October 2026: 0.86%3 October 202626 October 2026

EPSS moved from 0.9% on 3 October 2026 to 0.9% on 26 October 2026.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.