CVE-2026-67278
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.
How to fix
- mikrotik routeros7.23.6, 7.24.3 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mikrotik routeros | 7.0 ≤ v < 7.23.6, 7.24 ≤ v < 7.24.3 | 7.23.6, 7.24.3 |
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