CVE-2026-86060: SSH session privilege manipulation via a crafted username in Mikrotik RouterOS

Q: Which deployments are exposed to exploitation?

Deployments where an unauthenticated SSH session can reach the RouterOS login helper are exposed. The issue affects MikroTik RouterOS versions earlier than the fixed releases in their respective trains.

Q: What does an attacker need to exploit this issue?

An attacker needs network access to establish an unauthenticated SSH session to the RouterOS login helper. The flaw is triggered through a crafted username beginning with a prohibited character.

Q: Which RouterOS releases contain the fix?

The issue was fixed in RouterOS 6.49.21 (Long-term), 7.23.4 (Long-term), and 7.24.2 (Stable).

Q: How can exposure be reduced if an update cannot be applied immediately?

Restrict unauthenticated SSH access so that attackers cannot reach the RouterOS login helper. The provided data does not identify additional mitigations or indicators of compromise.

Published Sep 5, 2026

Updated

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 (Lont-term), 7.23.4 (Lont-term) and 7.24.2 (Stable)

Affected Software

1 affected component

Mikrotik RouterOS<=6.49.20, <=7.23.3, <=7.24.1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade MikroTik RouterOS to a version that resolves this vulnerability.
Fixed in 6.49.21
Upgrade
Upgrade MikroTik RouterOS to a version that resolves this vulnerability.
Fixed in 7.23.4
Upgrade
Upgrade MikroTik RouterOS to a version that resolves this vulnerability.
Fixed in 7.24.2

Event History

Sep 5, 2026

CVE Published

via MITRE·08:00 PM

Data Sourced

via MITRE·08:00 PM

DescriptionWeakness

Frequently Asked Questions

Which deployments are exposed to exploitation?

Deployments where an unauthenticated SSH session can reach the RouterOS login helper are exposed. The issue affects MikroTik RouterOS versions earlier than the fixed releases in their respective trains.

What does an attacker need to exploit this issue?

An attacker needs network access to establish an unauthenticated SSH session to the RouterOS login helper. The flaw is triggered through a crafted username beginning with a prohibited character.

Which RouterOS releases contain the fix?

The issue was fixed in RouterOS 6.49.21 (Long-term), 7.23.4 (Long-term), and 7.24.2 (Stable).

How can exposure be reduced if an update cannot be applied immediately?

Restrict unauthenticated SSH access so that attackers cannot reach the RouterOS login helper. The provided data does not identify additional mitigations or indicators of compromise.

CVE-2026-86060: SSH session privilege manipulation via a crafted username in Mikrotik RouterOS

Affected Software

Remediation

Event History

Frequently Asked Questions

Which deployments are exposed to exploitation?

What does an attacker need to exploit this issue?

Which RouterOS releases contain the fix?

How can exposure be reduced if an update cannot be applied immediately?

Company

Resources

Contact

Frequently Asked Questions

Which deployments are exposed to exploitation?

What does an attacker need to exploit this issue?

Which RouterOS releases contain the fix?

How can exposure be reduced if an update cannot be applied immediately?