CVE-2024-56412Public exploitNetwork attack vector

Browser script execution via whitespace-obfuscated hyperlink schemes

Published Jan 3, 2025 · Updated Jan 3, 2025

Cross-site scripting in PHPOffice PhpSpreadsheet allows remote authenticated users to execute JavaScript through crafted spreadsheet hyperlinks. The Html writer's generateRow method decoded hyperlink URLs but matched only contiguous word characters before the colon, so tab, carriage-return, or newline characters split the javascript scheme and bypassed its allowlist. Exploitation requires an application to convert the malicious spreadsheet to HTML and a user to view the generated page, placing browser data and actions in the page's origin at risk.

CVSS severity4.8
Medium
EPSS probability0.38%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in PHPOffice PhpSpreadsheet allows remote authenticated users to execute JavaScript through crafted spreadsheet hyperlinks. The Html writer's generateRow method decoded hyperlink URLs but matched only contiguous word characters before the colon, so tab, carriage-return, or newline characters split the javascript scheme and bypassed its allowlist. Exploitation requires an application to convert the malicious spreadsheet to HTML and a user to view the generated page, placing browser data and actions in the page's origin at risk.

The record

CVE
CVE-2024-56412
Published
Jan 3, 2025
Updated
Jan 3, 2025
Vendor
PHPOffice
Product
PhpSpreadsheet
Classifications
CWE-79, T1203, T1204.002
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 3, 2025CVE publishedPublication date reported by the CVE source.
  2. Jan 3, 2025Record 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=< 1.29.7
  2. Affected versionversion=>= 2.0.0, < 2.1.6
  3. Affected versionversion=>= 2.2.0, < 2.3.5
  4. Affected versionversion=>= 3.0.0, < 3.7.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

PHPOffice · PhpSpreadsheetversion=< 1.29.7; version=>= 2.0.0, < 2.1.6; version=>= 2.2.0, < 2.3.5; version=>= 3.0.0, < 3.7.0

Published CVSS scores

5.4NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.8GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution
T1204.002Malicious 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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