CVE-2026-23873

CRITICALNVD 9.09.0—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.0 under NVD CVSS v3. EPSS exploit probability: 0.5%, top 60% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, nvd
Elevated
9.0
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 1%CVSS: 9.0Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
9.0
EG Score
9.0(medium)
EG Risk
57(Track)
EG Risk 57/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
40.5%
KEV
Not listed

Published

January 22, 2026

Last Modified

February 27, 2026

Advisory Details (1)

Auto-updated Jun 8, 2026
Patch available. Sources: github.
github Patch Available

Stored CSV Injection (Formula Injection) in Contest Rank Export Leading to RCE Risk · Advisory · zhblue/hustoj · GitHub

https://github.com/zhblue/hustoj/security/advisories/GHSA-gqwv-v7vx-2qjw

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 13× in last 7d / 52× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 03:07 UTCEG score recompute
  2. 2026-07-22 14:08 UTCEPSS rescore
  3. 2026-07-21 15:24 UTCEPSS rescore
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  19. 2026-07-13 21:08 UTCOSV refresh
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  1. 2026-07-08 15:15 UTCEPSS rescore
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  20. 2026-06-27 03:08 UTCEPSS rescore
  21. 2026-06-25 18:46 UTCOSV refresh
  22. 2026-06-25 13:49 UTCEPSS rescore
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  68. 2026-05-31 22:30 UTCEPSS rescore
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  70. 2026-05-29 15:29 UTCEG score recompute
  71. 2026-05-29 13:44 UTCEPSS rescore
  72. 2026-05-29 13:44 UTCEPSS rescore

Frequently asked(5)

What is CVE-2026-23873?
CVE-2026-23873 is a critical vulnerability published on January 22, 2026. 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…
When was CVE-2026-23873 disclosed?
CVE-2026-23873 was first published in the National Vulnerability Database on January 22, 2026, with the most recent update on February 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-23873 actively exploited?
CVE-2026-23873 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 40.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-23873?
CVE-2026-23873 has a CVSS v3 base score of 9.0 (NVD).
How do I remediate CVE-2026-23873?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-23873, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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