CVE-2026-23873Public exploitNetwork attack vector

Administrator code execution via unsanitized rank exports

Published Jan 21, 2026 · Updated Jan 21, 2026

CSV injection in zhblue HUSTOJ 26.01.01 and earlier allows remote authenticated users to execute formulas through exported rank lists. contestrank.xls.php and admin/ranklist_export.php write the stored Nickname value directly into an HTML-table .xls cell without neutralizing leading formula characters. Exploitation requires an administrator to export the rank list and open it in Microsoft Excel, where the formula can execute commands or exfiltrate data on the administrator's machine.

CVSS severity5.2
Medium
EPSS probability0.53%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSV injection in zhblue HUSTOJ 26.01.01 and earlier allows remote authenticated users to execute formulas through exported rank lists. contestrank.xls.php and admin/ranklist_export.php write the stored Nickname value directly into an HTML-table .xls cell without neutralizing leading formula characters. Exploitation requires an administrator to export the rank list and open it in Microsoft Excel, where the formula can execute commands or exfiltrate data on the administrator's machine.

The record

CVE
CVE-2026-23873
Published
Jan 21, 2026
Updated
Jan 21, 2026
Vendor
zhblue
Product
HUSTOJ
Classifications
CWE-1236, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 21, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=<= 26.01.01

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

zhblue · HUSTOJversion=<= 26.01.01

Published CVSS scores

9.0NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H
5.2GitHub, Inc.CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-1236Improper Neutralization of Formula Elements in a CSV File
T1204.002User Execution: Malicious File

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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