VULNERABILITY INTELLIGENCE

CVE-2026-23873

CVSS score9 CRITICAL
EPSS probability0.57%
CISA KEVNot currently listed
Published2026-01-22
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H

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 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.

Weakness classification

  • security-advisories@github.com: CWE-1236

Primary references