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Vulnerability record · CVE-2026-84411 · published 2 October 2026

CVE-2026-84411: The web management service in affected RouterOS versions contains an integer underflow in its HTTP request bod…

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.

9.3 CVSS 4.0 Critical CWE-191 · CWE-191 Received
9.3CVSS 4.0 base score
-EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
2 Oct 2026Last modified by NVD

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/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/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
https://github.com/cisagov/CSAF/blob/develop/csaf_files/OT/white/2026/icsa-26-272-06.json
https://mikrotik.com/download
https://www.cisa.gov/news-events/ics-advisories/icsa-26-272-06

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2014-0497Adobe Flash Player integer underflow allows remote code executionAdobe Flash Player contains an integer underflow (CWE-191) that allows remote attackers to execute arbitrary code via unspecified vectors. The flaw a…KEVEPSS 100%analysed8.4CVE-2022-0185Linux Kernel Filesystem Context Heap Buffer OverflowThe legacy_parse_param function in the Linux kernel's Filesystem Context functionality fails to properly verify supplied parameter lengths, causing a…KEVEPSS 25%analysed7.8CVE-2021-31956Windows NTFS integer underflow privilege escalationCVE-2021-31956 is an elevation of privilege flaw in the Windows NTFS file system driver, rooted in an integer underflow (CWE-191). A local attacker w…KEVEPSS 22%analysed

Source: NIST National Vulnerability Database (record CVE-2026-84411), CISA KEV, FIRST EPSS. This page is refreshed as NVD updates the record.