CVE-2026-67278: mikrotik routeros

Vulnerability summary

CVE-2026-67278 is a critical (CVSS 9.1) vulnerability in mikrotik routeros. EPSS estimates a 0.25% chance of exploitation in the next 30 days, higher than 15.7% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 05-09-2026
   PublishedVulnerability first disclosed.
2. 17-09-2026
   Last modifiedVulnerability information updated.

Description

MikroTik RouterOS accepts malformed RSA/PKCS#1 v1.5 signatures across RSA-based services, including TLS/X.509 certificate validation and SSH host-key authentication. Because its trust store includes an e=3 root CA, an attacker controlling or redirecting an outbound RouterOS TLS connection can use the root’s public certificate - without its private key - to forge a trusted intermediate and issue certificates for arbitrary hostnames, enabling TLS server impersonation. The same permissive verification also undermines RSA-based SSH authentication. This issue affects only 7.x branch was fixed in versions: 7.23.6 (Long-term) and 7.24.3 (Stable). Releases 7.23.4 and 7.24.2 included an incomplete fix.

• CWE-347Improper Verification of Cryptographic SignatureThe product does not verify, or incorrectly verifies, the cryptographic signature for data.