CVE-2025-42611: MikroTik RouterOS

Medium severity, CVSS 6.5. EPSS: 0.2% chance of exploitation in the next 30 days.

RouterOS provides various services that rely on correct verification of client and server certificates to secure confidentiality and integrity of communications. This includes OpenVPN, CAPsMAN, Dot1x (802.1X), among others. The vulnerability lies in shared certificate validation logic which uses the system certificate store that is shared and equally trusted by all system services. This causes confusion of scope, allowing any certificate authority present in the system-wide trust store to be trusted in any context (with some exceptions), allowing partial or full authentication bypass in CAPsMAN, OpenVPN, Dot1X and potentially others.

Affected products

• MikroTik RouterOS: before 7.21 (fixed in 7.21)

Published 2026-05-05. Last modified 2026-10-07.