An issue was discovered in PHP 7.x before 7.1.27 and 7.3.x before 7.3.3. phar_tar_writeheaders_int in ext/phar/tar.c has a buffer overflow via a long link value. NOTE: The vendor indicates that the link value is used only when an archive contains a symlink, which currently cannot happen: "This issue allows theoretical compromise of security, but a practical attack is usually impossible.