Cyber Threat Intelligence
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CRITICAL · CVSS 9.8 CISA Known Exploited Vulnerability

CVE-2026-86060

MikroTik RouterOS Improper Neutralization of Argument Delimiters in a Command Vulnerability

MikroTik RouterOS

RouterOS contains an argument-handling flaw in the SSH login path involving usernames that begin with a prohibited character, allowing for the trusted RouterOS policy mask to be changed, leading to privilege escalation. Exploitation requires an unauthenticated SSH session to reach the RouterOS login helper.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

CVSS
9.8
CRITICAL
EPSS
1.1%
30-day exploitation
Ransomware groups
0
recorded exploiting
Published
5 Sep 2026
CWE-88

Exploitation status

CISA Known Exploited Vulnerabilities

Listed by CISA on 10 September 2026. US federal agencies were required to remediate it by 13 September 2026.

EPSS — exploitation probability

FIRST puts the probability of exploitation activity in the next 30 days at 1.1%, which is higher than 62.8% of all scored vulnerabilities. EPSS is a forecast of activity, not a measure of severity, and it is rescored daily.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Frequently asked questions

Is CVE-2026-86060 being exploited by ransomware groups?

No ransomware group in this database is currently recorded as exploiting CVE-2026-86060.

What does CVE-2026-86060 affect?

CVE-2026-86060 affects MikroTik RouterOS. RouterOS contains an argument-handling flaw in the SSH login path involving usernames that begin with a prohibited character, allowing for the trusted RouterOS policy mask to be changed, leading to privilege escalation. Exploitation requires an unauthenticated SSH session to reach the RouterOS login helper.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

How severe is CVE-2026-86060?

CVE-2026-86060 is rated CRITICAL with a CVSS base score of 9.8. EPSS puts the probability of exploitation in the next 30 days at 1.1%, higher than 62.8% of all scored vulnerabilities. It is listed in the CISA Known Exploited Vulnerabilities catalog, with a federal remediation deadline of 13 September 2026.

How should organisations respond to CVE-2026-86060?

Apply the vendor patch for MikroTik RouterOS as the first priority, and treat any internet-facing instance as the most urgent. Because this vulnerability is associated with ransomware activity, also review whether the affected systems were reachable before patching, rather than assuming that patching alone closes the incident.