Nullsoft Scriptable Install System (NSIS) before 3.11 on Windows allows local users to escalate privileges to SYSTEM during an installation, because the temporary plugins directory is created under %…

Summary

Nullsoft Scriptable Install System (NSIS) before 3.11 on Windows allows local users to escalate privileges to SYSTEM during an installation, because the temporary plugins directory is created under %WINDIR%\temp and unprivileged users can place a crafted executable file by winning a race condition. This occurs because EW_CREATEDIR does not always set the CreateRestrictedDirectory error flag.