CWE-281 (权限预留不恰当) — Vulnerability Class 91

CWE-281 represents a critical security weakness where software fails to maintain the intended access controls during file operations such as copying, restoring, or sharing. This flaw typically arises when developers rely on default system behaviors that reset permissions to more permissive states, inadvertently exposing sensitive data to unauthorized users. Attackers exploit this vulnerability by manipulating file transfer processes to gain elevated privileges or access restricted resources that should remain private. To mitigate this risk, developers must explicitly enforce permission preservation by using secure APIs that retain original access control lists during object manipulation. Implementing strict validation checks and avoiding generic file copy functions in favor of secure alternatives ensures that security boundaries remain intact. Regular code reviews focusing on file handling routines further help identify and correct these oversights before deployment.