SiYuan Windows installer before version 3.8.1 (affected versions >= 2.0.14) contains an uncontrolled search path element vulnerability in its NSIS installer, which invokes system executables such as TASKKILL by name rather than by absolute path. Because NSIS nsExec::Exec resolves these calls using a search path that includes the installer's own launch directory ahead of System32, an attacker who plants a malicious executable (e.g., a renamed TASKKILL.exe) in that directory can have it executed when the installer runs. These calls occur in electron-builder's preInit hook before the license page is displayed, and with an all-users (elevated) install the planted binary executes with an elevated token, resulting in local privilege escalation.