CVE-2026-67278CWE-347

CVE-2026-67278

published September 6, 2026

CVSS
6.3
EPSS
0%
Percentile
6.3
In the wild
Unconfirmed
What it is

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)

The record
Technical detail
CVSS
6.3 · NONE
CVSS v4.0
6.3 · 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
EPSS
0.00167 · 6.3th percentile
Weakness
CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-09-06T00:17Z
References (7)
https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve · [email protected]https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/ · [email protected]https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 · [email protected]https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 · [email protected]https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 · [email protected]https://mikrotik.com/supportsec/september-2026-vulnerability/ · [email protected]https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ · [email protected]
EPSS history
Timeline
  • 07 SEP 03:35Z
    EPSS moved — → 0%
    epss
  • 05 SEP 20:00Z
    TLS server impersonation possible in Mikrotik RouterOS
    cvelistv5