TLS server impersonation possible in Mikrotik RouterOS

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-67278
StatePUBLISHED
AssignerCERT-PL
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-05 20:17:18 UTC
Updated2026-09-05 21:16:50 UTC
DescriptionMikroTik 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)

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from [email protected]

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

Problem Types: CWE-347 | CWE-347 CWE-347 Improper verification of cryptographic signature

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.3MEDIUMCVSS: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/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Sub Conf.
None
Sub Integrity
None
Sub Availability
None

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mikrotik RouterOS affected 7.24 7.24.2 custom Not specified
CNA Mikrotik RouterOS affected 7.0.0 7.23.4 custom Not specified
CNA Mikrotik RouterOS affected 6.0.0 6.49.21 custom Not specified

References

ReferenceSourceLinkTags
cert.pl/en/posts/2026/09/mikrotik-routeros-cve [email protected] cert.pl
npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they... [email protected] npratley.net
forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 [email protected] forum.mikrotik.com
cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-activel... [email protected] cert.pl
forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 [email protected] forum.mikrotik.com
forum.mikrotik.com/t/7-24-2-stable-is-released/272800 [email protected] forum.mikrotik.com
mikrotik.com/supportsec/september-2026-vulnerability [email protected] mikrotik.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Sławomir Rozbicki (CERT.PL) (en)

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