Affected versions of the pip package are vulnerable to Path Traversal due to an incorrect directory containment check when extracting wheel archives. In src/pip/_internal/utils/unpacking.py, the is_within_directory() helper used os.path.commonprefix() (character-by-character) to compare directory and target paths, allowing crafted paths like a parent-directory substring match to be treated as safely inside the installation directory.

Affected versions of the pip package are vulnerable to Arbitrary File Overwrite due to improper validation of symbolic link targets in the fallback tar extraction code. In src/pip/_internal/utils/unpacking.py, the _untar_without_filter routine used when the Python tarfile module lacks PEP 706 (no tarfile.data_filter) extracted symlink members with tar._extract_member without verifying that link destinations resolve under the extraction root, a check later added via the is_symlink_target_in_tar helper.

Pip solves a security vulnerability that previously allowed maliciously crafted wheel files to execute unauthorized code during installation.