CVE-2026-67278 json
TLS server impersonation possible in Mikrotik RouterOS
published 2026-09-05 2 mo ago modified 2026-09-25 45 d ago also EUVD-2026-72026
- cvss
- 9.1
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.3%
- EPSS 0.3% chance of exploitation in 30 days, percentile 17%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- Mikrotik RouterOS 7.23.6, 7.24.3
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 mo ago
Exploit prediction
0.26% chance of exploitation in the next 30 days, higher than 17% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- npratley.net https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 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 |
| CNA | 4.0 | 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 | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
Affected products
- Mikrotik RouterOS
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
npratley.net
/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
exploit, third-party-advisory
-
mikrotik.com
/supportsec/september-2026-vulnerability/
vendor-advisory
-
cert.pl
/en/posts/2026/09/mikrotik-routeros-cve
third-party-advisory
-
cert.pl
/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
technical-description, mitigation, third-party-advisory
-
forum.mikrotik.com
/t/7-23-6-long-term-is-released/273139
release-notes
-
forum.mikrotik.com
/t/7-24-3-stable-is-released/273138
release-notes
Sources
- CVE List CVE-2026-67278
- NVD CVE-2026-67278
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.