CVE-2026-67279 PUBLISHED

SSH Pre-Authentication Rekey State Bypass in MikroTik RouterOS

Assigner: CERT-PL
Reserved: 29.07.2026 Published: 05.09.2026 Updated: 05.09.2026

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)

Metrics

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
CVSS Score: 6.9

Product Status

Vendor Mikrotik
Product RouterOS
Versions Default: unaffected
  • affected from 7.24 to 7.24.2 (excl.)
  • affected from 7.0.0 to 7.23.4 (excl.)
  • affected from 6.0.0 to 6.49.21 (excl.)

Credits

  • Sławomir Rozbicki (CERT.PL) finder

References

Problem Types

  • CWE-841 Improper enforcement of behavioral workflow CWE