openssl_encrypt before 1.4.9 Plugin Sandbox Path Traversal

openssl_encrypt (pip: openssl-encrypt) versions before 1.4.9 contain a path traversal flaw in PluginSandbox._is_safe_path, which authorized file access using a bare string-prefix match. A sandboxed plugin without the READ_FILES permission could read or write another plugin's directory that merely shares a name prefix (e.g., .../plugins/foobar matching allowed .../plugins/foo), breaking per-plugin isolation within the same user. Fixed by matching each allowed directory exactly or with a trailing path separator.