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.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
1Patches
Vulnerability mechanics
References
6- npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/nvdExploitThird Party Advisory
- cert.pl/en/posts/2026/09/mikrotik-routeros-cvenvdThird Party Advisory
- cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/nvdMitigationThird Party Advisory
- mikrotik.com/supportsec/september-2026-vulnerability/nvdVendor Advisory
- forum.mikrotik.com/t/7-23-6-long-term-is-released/273139nvdRelease Notes
- forum.mikrotik.com/t/7-24-3-stable-is-released/273138nvdRelease Notes
News mentions
2- MikroTik Patches Critical Flaws Chained to Hack RoutersSecurityWeek · Sep 8, 2026
- ⚡ Weekly Recap: Chrome 0-Day, Router Hijacks, Coder Supply Chain Attack and MoreThe Hacker News · Sep 7, 2026