CVE-2026-67278
MikroTik · published 2026-09-05
Source record Collected from the National Vulnerability Database (NVD)
Description
Description by CERT.PL via the CVE Program.
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.
Filed by CERT.PL; not a statement by MikroTik.
Status at the source
- NVD status: Analyzed
Affected products, as the source lists them
| Vendor | Product | Versions |
|---|---|---|
| Mikrotik | RouterOS | 7.24 – before 7.24.3: affected 7.0.0 – before 7.23.6: affected |
Products named in NVD's CPE match criteria (1)
cpe:2.3:o:mikrotik:routeros:*:*:*:*:*:*:*:*
DeSpy has not checked any unit, hardware revision or firmware. A product missing here is not a statement that it is unaffected.
Scores, as their sources published them
- CVSS 4.0: 6.3 MEDIUM — as published by CERT.PL (Secondary)
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 - CVSS 3.1: 9.1 CRITICAL — as published by NIST (Primary)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - SSVC — CISA's assessment (SSVC 2.0.3, CISA Coordinator): Exploitation: poc · Automatable: no · Technical impact: partial
DeSpy does not score records. These are the sources' own values.
Weaknesses
Sources
References the source lists
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
- 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
- https://mikrotik.com/supportsec/september-2026-vulnerability/
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
Source dates: published 2026-09-05, last changed 2026-09-25. DeSpy's copy of this version is dated 2026-09-28.
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