CVE-2026-24479: HUSTOJ has Arbitrary File Write (Zip Slip) in Problem Import Modules that leads to RCE

HUSTOF is an open source online judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training. Prior to version 26.01.24, the problem_import_qduoj.php and problem_import_hoj.php modules fail to properly sanitize filenames within uploaded ZIP archives. Attackers can craft a malicious ZIP file containing files with path traversal sequences (e.g., ../../shell.php). When extracted by the server, this allows writing files to arbitrary locations in the web root, leading to Remote Code Execution (RCE). Version 26.01.24 contains a fix for the issue.