Status: UPDATED | Advisory ID: CVE-2026-67278
| CVE | CVE-2026-67278 |
| CVSS Score / Version | 9.1 (Critical) / CVSS v3.1 |
| Updated | 2026-09-25 |
| CVSS Vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
| CVSS Prose | attack vector is network; attack complexity is low; privileges required is none; user interaction is none; scope is unchanged; confidentiality impact is high; integrity impact is high; availability impact is none. |
| Affected products | MikroTik RouterOS |
| Classified as | CWE-347 (Improper Verification of Cryptographic Signature) |
| Vendor | Product | Affected Versions | Patch Status |
|---|---|---|---|
| MikroTik | RouterOS |
| Subsystems | Industrial Network - Routers/Firewalls |
| Sectors | Multi-sector |
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. (NVD)
Monitor MikroTik's web page for any future patch releases. See vendor advisory link below.
| Source | Reference |
|---|---|
| NVD | https://nvd.nist.gov/vuln/detail/CVE-2026-67278 |
| CVE | https://www.cve.org/CVERecord?id=CVE-2026-67278 |
| Vendor advisory | https://mikrotik.com/supportsec/september-2026-vulnerability/ |