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 during X.509 validation. 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.
This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)
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/6-49-21-long-term-is-released/272802
- https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801
- https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800
Metadata Profile
Database Authority
European Union Agency for Cybersecurity (ENISA) EUVD
Assigner
CERT-PL
EPSS Probability
0
Known Aliases
CVE-2026-67278
GHSA-cq44-x9vf-fpqg
Published On
2026-09-05
Last Updated
2026-09-05