The vulnerability stems from how Poetry resolved the Git executable path on Windows. The pre-patch code in git.py directly invoked 'git' commands without absolute path validation, making it susceptible to DLL search order hijacking. The fix introduced an executable() function that securely resolves the full system path to git.exe using Windows' where.exe utility. The vulnerable Git.run() method was modified to use this secure path resolution instead of relying on the ambient PATH variable, confirming this was the attack vector.