Critical

Zip Slip RCE in HUSTOJ problem import

IdentifiersCVE-2026-24479CWE-22· Improper Limitation of a Pathname…

CVE-2026-24479 affects HUSTOJ, an open source online judge platform based on PHP/C++/MySQL/Linux. In versions prior to 26.01.24, the problem_import_qduoj.php and problem_import_hoj.php modules do not properly sanitize filenames contained in uploaded ZIP archives during problem import. An authenticated attacker can supply a crafted archive containing path traversal sequences such as ../../shell.php. When the server extracts the archive, files can be written outside the intended extraction directory and into arbitrary locations reachable by the web server, including the web root. By planting a PHP file in a web-accessible location and then requesting it, the attacker can achieve remote code execution on the target system. The issue is a Zip Slip style arbitrary file write via archive extraction.

For your environment

Are you exposed to this one?

Mallory correlates every CVE against your assets, your vendors, and active adversary campaigns. Know which vulnerabilities matter for you, not just which ones are loud.

Start free trial

ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows arbitrary file write outside the intended ZIP extraction path. In the described attack path, this enables placement of attacker-controlled PHP code into the web root or another executable web-accessible directory, resulting in remote code execution in the context of the web server. Depending on deployment, this can lead to full compromise of the HUSTOJ application, theft or modification of judging data, administrative takeover, persistence via webshell deployment, and potential further compromise of the underlying host.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, restrict access to the problem import functionality to trusted administrators only and disable the affected import paths where feasible. Prevent the web server from executing uploaded or newly written script files in import and upload directories, and harden the web root so application workflows cannot write executable content there. Add server-side validation of ZIP entry names, reject archives containing traversal sequences or absolute paths, and monitor for suspicious imports and unexpected PHP files appearing under the document root.

Remediation

Patch, then assume compromise.

Upgrade HUSTOJ to version 26.01.24 or later, which contains the fix for this issue. Ensure ZIP extraction logic canonicalizes and validates each archive entry path before writing files, rejecting absolute paths and any entry that escapes the intended destination directory via .. traversal. Review the problem import implementation in problem_import_qduoj.php and problem_import_hoj.php for similar unsafe extraction patterns, and remove any attacker-written files that may already have been placed in web-accessible directories.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.

VALID 0 / 2 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

HustojHustojapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

4 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

4 SOURCESView more in app

metasploit pull requestsNews

Mar 20, 2026

Repull of HUSTOJ CVE-2026-24479 exploit by oxagast · Pull Request #21165 · rapid7/metasploit-framework · GitHub

A remote code execution vulnerability in HustOJ versions prior to 26.01.24, apparently exploitable via the problem import functionality using a Zip Slip path traversal to place and execute a PHP payload.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

Start free trial

Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity3