CWE-276 is a weakness category for incorrect default permissions on files or directories. It appears when software, installers, or system administrators create paths that are too open, allowing standard users to read, modify, or execute content that should be restricted. These permission mistakes are especially dangerous on shared systems because they can expose configuration files, writable search-path locations, logs, or program directories to unintended tampering.
In cyber security, CWE-276 matters because weak directory permissions often become the first step in privilege escalation or code execution attacks. For example, if a privileged application loads files from a writable directory, an attacker may plant a malicious DLL or replace a trusted file and wait for an administrator to run the program. Defenders reduce this risk by applying least privilege, tightening ACLs, auditing writable paths, and verifying that sensitive applications do not rely on user-controlled directories.