How severe is CVE-2026-23873?

This vulnerability has a CVSS score of (Unknown severity).

How difficult is it to exploit CVE-2026-23873?

Exploit difficulty: HARD. Estimated time to exploit: > 4 hours. Required skills: Advanced security expertise.

CVE-2026-23873 - YourPassGen

hustoj is an open source online judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training. All versions are vulnerable to CSV Injection (Formula Injection) through the contest rank export functionality (contestrank.xls.php and admin/ranklist_export.php). The application fails to sanitize user-supplied input (specifically the “Nickname” field) before exporting it to an .xls file (which renders as an HTML table but is opened by Excel). If a malicious user sets their nickname to an Excel formula when an administrator exports and opens the rank list in Microsoft Excel, the formula will be executed. This can lead to arbitrary command execution (RCE) on the administrator’s machine or data exfiltration. A fix was not available at the time of publication.

Related CVE by CWE

No related CWE found.

Top CVE for Vendor

No vendor taxonomy on this entry.

Recently Exploited Similar Vulnerabilities

No recent KEV-listed items for this vendor/product.

How to fix CVE-2026-23873

CVE-2026-23873 is a unknown severity vulnerability affecting the affected product.

Description: hustoj is an open source online judge based on PHP/C++/MySQL/Linux for ACM/ICPC and NOIP training. All versions are vulnerable to CSV Injection (Formula Injection) through the contest rank export functionality (contestrank.xls.php and admin/ranklist_export.php). The application fails to sanitize user-supplied input (specifically the “Nickname” field) before exporting it to an .xls file (which renders as an […]

Exploit Difficulty: HARD
⏱️ Time to exploit: > 4 hours
🛠️ Required skills: Advanced security expertise
💰 Public exploits: Rare or not public

How to Fix:

1 Identify affected systems

- Check if you're running the affected product

2 Immediate actions

- Update to the latest patched version
- If patching is not immediately possible: restrict network exposure, apply least-privilege access

3 Verification

- Test the fix in a staging environment first
- Review logs for signs of exploitation
- Monitor for IOCs (Indicators of Compromise)

4 Long-term prevention

- Enable automatic security updates
- Set up vulnerability monitoring
- Review and harden security configurations

Full CVE details

Exploit Difficulty Assessment

HARD

⏱️ Time to Exploit: > 4 hours

🛠️ Skills Required: Advanced security expertise

💰 Public Exploits: Rare or not public

Vulnerability Timeline

Jan 22, 2026

Vulnerability Published

CVE details first published to NVD database

Jan 22, 2026

Imported to Database

Added to this CVE tracking system

Detection Rules & IOCs

No specific detection rules generated for this vulnerability type.

No vendor/product data available.

No related CVEs found (no vendor/product data available).