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Improper Privilege Management


Severity High
Score 8/10


Tailscale is software for using Wireguard and multi-factor authentication (MFA). A vulnerability identified in the implementation of Tailscale SSH starting in version 1.34.0 through 1.38.1 in FreeBSD allows commands to be run with a higher privilege group ID than that specified in Tailscale SSH access rules. A difference in the behavior of the FreeBSD "setgroups" system call from POSIX meant that the Tailscale client running on a FreeBSD-based operating system did not appropriately restrict groups on the host when using Tailscale SSH. When accessing a FreeBSD host over Tailscale SSH, the "egid" of the tailscaled process was used instead of that of the user specified in Tailscale SSH access rules. Tailscale SSH commands may have been run with a higher privilege group ID than that specified in Tailscale SSH access rules if they met all of the following criteria: the destination node was a FreeBSD device with Tailscale SSH enabled; Tailscale SSH access rules permitted access for non-root users; and a non-interactive SSH session was used.

  • LOW
  • HIGH
  • NONE
  • LOW
  • HIGH
  • HIGH

CWE-269 - Improper Privilege Management

An effective privilege management infrastructure provides valid users with required access and privileges across heterogeneous technology environments. An application with a faulty privilege management infrastructure allows higher than authorized privileges or enables privilege escalation. This can lead to security incidents such as system infiltration, data breach, and complete system takeover.

Advisory Timeline

  • Published