CVE-2026-67277

MikroTik RouterOS Missing Authentication for Critical Function Vulnerability

Routeros

RouterOS accepts a "related" btest connection before the corresponding primary session has completed authentication. An unauthenticated client can use this state to start an IPv4 UDP test. With "random-data=false", the sender transmits an uninitialized tail from a kernel packet buffer. A separate unchecked, inverted packet-size interval causes unsigned integer underflow, anomalously large fragmented output, and can restart the RouterOS kernel. This issue was fixed in…

5. Sep 2026

Ausgewertete Quellen

• Hersteller
  https://mikrotik.com/supportsec/september-2026-vulnerability/
• Hinweis
  https://cert.pl/en/posts/2026/09/mikrotik-routeros-cve
• Hinweis
  https://cert.pl/en/posts/2026/09/vulnerabilities-in-mikrotik-routeros-actively-exploited/
• Hinweis
  https://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/
• CISA
  https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67277
• CISA
  MikroTik RouterOS Missing Authentication for Critical Function Vulnerability
• NVD
  CVE-2026-67277