PHPUnit is a testing framework for PHP. From 13.4.0 until 13.4.4, the TestCase::coverageFilesDirectory() logic in src/Runner/Phpt/TestCase.php creates temporary files for PHPT code coverage in a predictable phpunit-phpt directory under sys_get_temp_dir() and reuses that directory without verifying its ownership or permissions. On multi-user systems with a shared temporary path, a local attacker who creates the directory before the developer runs PHPT tests with code coverage can replace the generated job file before the child process executes it with require, allowing arbitrary code execution with the developer's privileges while the test and coverage report appear successful. PHPUnit 12.5 and earlier, default macOS and Windows configurations with per-user temporary directories, and single-user environments where another user cannot create files in the temporary path are not affected. This issue is fixed in 13.4.4.