EUVD Vulnerability Catalog
EUVD-2026-72026
Severity: MEDIUM
Base Score: 6.3
CVSS Version: 4.0
Vulnerability 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.
CVSS Vector Analysis
Below is the complete, human-readable breakdown of the CVSS metric string: 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
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Attack Vector (AV): Network
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Attack Complexity (AC): Low
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Attack Requirements (AT): Present
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Privileges Required (PR): None
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User Interaction (UI): None
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Vulnerability Confidentiality Impact (VC): Low
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Vulnerability Integrity Impact (VI): Low
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Vulnerability Availability Impact (VA): None
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Subsequent Confidentiality Impact (SC): None
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Subsequent Integrity Impact (SI): None
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Subsequent Availability Impact (SA): None
Affected Vendors & Systems
Vendor
MikroTik
References & Advisory Links
- 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
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
CERT-PL
EPSS Probability
0.16
Known Aliases
CVE-2026-67278
GHSA-cq44-x9vf-fpqg
Published On
2026-09-05
Last Updated
2026-09-17