TLS server impersonation possible in Mikrotik RouterOS
Published Sep 5, 2026
6.3
MEDIUMCVSS 4.0
EPSS 0.25%
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.
Affected products
-
- Version 7.0.0StatusaffectedConstraints<7.23.6
- Version 7.24StatusaffectedConstraints<7.24.3
- Version
No data.
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
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
1 other source (NVD) ▾
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
No CVSS v3.1 score for this CVE.
No CVSS v3.0 score for this CVE.
No CVSS v2.0 score for this CVE.
This CVE is not in the KEV list.
CISA SSVC (Vulnrichment)
Stakeholder-Specific Vulnerability Categorization from CISA ADP.
Exploitation
PoCAutomatable
NoTechnical Impact
PartialDecision
n/aAssessed Sep 8, 2026 · SSVC 2.0.3
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
Sep–Oct 2026- EPSS v5
Percentile over time
- EPSS v5
Table of values (2 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 0.25% (0.00252) | 15.08th | v5 (v2026.06.15) |
| Sep 6, 2026 | 0.17% (0.00167) | 6.25th | v5 (v2026.06.15) |
References (6)
- https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve third-party-advisory
- https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ technical-description
- https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139 release-notes
- https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138 release-notes
- https://mikrotik.com/supportsec/september-2026-vulnerability/ vendor-advisory
- https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ exploit
| Link | Providers | Tags |
|---|---|---|
| https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve | third-party-advisory | |
| https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ | technical-description | |
| https://forum.mikrotik.com/t/7-23-6-long-term-is-released/273139 | release-notes | |
| https://forum.mikrotik.com/t/7-24-3-stable-is-released/273138 | release-notes | |
| https://mikrotik.com/supportsec/september-2026-vulnerability/ | vendor-advisory | |
| https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ | exploit |
Change history (0)
No recorded changes yet.