Vulnerability details

RouterOS SSH enters the connection protocol after a client-requested rekey even though user authentication was never attempted, allowing an unauthenticated client to open a session channel and send an exec request. On affected builds the server dispatches the command, enabling unauthenticated creation, overwrite, and reconstruction of files in the RouterOS managed file namespace, including support files containing configuration and diagnostic data.This issue was fixed in versions: 6.49.21 (Long-term), 7.23.4 (Long-term) and 7.24.2 (Stable)

• 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://npratley.net/reversing-mikrotiks-silent-patch-the-routeros-7-23-4-fix-they-wouldnt-explain/ exploit
• https://mikrotik.com/supportsec/september-2026-vulnerability/ vendor-advisory
• https://forum.mikrotik.com/t/6-49-21-long-term-is-released/272802 release-notes
• https://forum.mikrotik.com/t/7-23-4-long-term-is-released/272801 release-notes
• https://forum.mikrotik.com/t/7-24-2-stable-is-released/272800 release-notes
• https://bishopfox.com/blog/mikrotrick-inside-the-routeros-takeover-chain third-party-advisory
• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-67279 government-resource