CVE-2026-67278TLS server impersonation possible in Mikrotik RouterOS
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 6.3 MEDIUM (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- Weakness (CWE)
- CWE-347
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- CERT-PL
- NVD analysis
- Analyzed
- Record last updated
- Sep 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Mikrotik RouterOS mikrotik:routeros (from the name) | from 7.24 before 7.24.3; from 7.0.0 before 7.23.6 | CNA record |
mikrotik routeros mikrotik:routeros | from 7.0 before 7.23.6; from 7.24 before 7.24.3 | NVD |
References
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cvethird-party-advisory
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/technical-description, mitigation, third-party-advisory
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/exploit, third-party-advisory
- https://mikrotik.com/supportsec/september-2026-vulnerability/vendor-advisory
- https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139release-notes
- https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.