CVE-2026-67278
TLS server impersonation possible in Mikrotik RouterOS
At a glance
- Source
- NVD
- EPSS
- EPSS 0.26 % · percentile 18 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- CERT-PL
- NVD status
- Analyzed
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.
Weaknesses (CWE)
- CWE-347 — Improper Verification of Cryptographic Signature
References
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
- https://mikrotik.com/supportsec/september-2026-vulnerability/
- https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139
- https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | MEDIUM 6.3 | 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 | CERT-PL |
| CVSS 4.0 | MEDIUM 6.3 | 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD · cvd@cert.pl (Secondary) |
| CVSS 3.1 | CRITICAL 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-72026
- GCVE · GCVE-0-2026-67278
Affected configurations (NVD CPE)
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*≥ 7.0 < 7.23.6cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*≥ 7.24 < 7.24.3
Affected products
| Product | Versions |
|---|---|
| Mikrotik · RouterOS | affected 7.24 < 7.24.3 ; affected 7.0.0 < 7.23.6 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |