How severe is CVE-2024-56411?

No CVSS score has been assigned to CVE-2024-56411 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2024-56411?

CVE-2024-56411 affects the following packages: phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpspreadsheet (Packagist), phpoffice/phpexcel (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2024-56411?

Update phpoffice/phpspreadsheet to 3.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56411 is resolved across your whole dependency graph.

How do I detect CVE-2024-56411 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpoffice/phpspreadsheet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2024-56411 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2024-56411?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-56411 can be triaged on real exposure rather than presence alone.

Is CVE-2024-56411 actively exploited in the wild?

No public exploit code has been indexed for CVE-2024-56411 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2024-56411?

CVE-2024-56411 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 27th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2024-56411?

CVE-2024-56411 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2024-56411 published, and has it been updated?

CVE-2024-56411 was published on January 3, 2025 and was last updated on August 12, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2024-56411 — phpoffice/phpspreadsheet

Fix: PHPOffice/PhpSpreadsheet@45052f8

CVE-2024-56411 is a Cross-site Scripting (XSS) vulnerability in phpoffice/phpspreadsheet. A fix is available for phpoffice/phpspreadsheet — see the affected versions and patch details below.

PhpSpreadsheet has Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header

Also known asGHSA-hwcp-2h35-p66w

Published

Jan 3, 2025

Updated

Aug 12, 2026

Affected

5 pkgs

Patched

4 / 5

Exploits

None indexed

Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2024-56411.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs27th percentile — riskier than 27% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Real-World Exposure

5 pkgs affected

🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpspreadsheet🐘phpoffice/phpexcel

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header

Product: Phpspreadsheet Version: version 3.6.0 CWE-ID: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') CVSS vector v.3.1: 5.4 (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) CVSS vector v.4.0: 4.8 (AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N) Description: the HTML page is formed without sanitizing the hyperlink base Impact: executing arbitrary JavaScript code in the browser Vulnerable component: class PhpOffice\PhpSpreadsheet\Writer\Html, method generateHTMLHeader Exploitation conditions: a user viewing a specially generated Excel file Mitigation: additional sanitization of special characters in a string Researcher: Aleksey Solovev (Positive Technologies)

Research

The researcher discovered zero-day vulnerability Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header in Phpspreadsheet. The following code is written on the server, which translates the XLSX file into a HTML representation and displays it in the response.

Listing 8. Source code on the server

<?php

require __DIR__ . '/vendor/autoload.php';

$inputFileName = './doc/Book1.xlsx';
$spreadsheet = \PhpOffice\PhpSpreadsheet\IOFactory::load($inputFileName);
$writer = new \PhpOffice\PhpSpreadsheet\Writer\Html($spreadsheet);
print($writer->generateHTMLAll());

An attacker can embed a payload in a file property that will result in the execution of arbitrary JavaScript code. The Excel file is unpacked and a HyperlinkBase in the file is inserted into the docProps/app.xml file.

fig14

Figure 14. Embedding the payload

After the changes were made, a new archive with the xlsx extension was created. At the moment of converting the xlsx file into the HTML representation, a property is obtained that participates in the formation of a string without sanitization.

fig15

Figure 15. Generating the HTML page header using the HyperlinkBase property

After generating and displaying the HTML representation of the XLSX file, arbitrary JavaScript code will be executed. <img width="356" alt="fig16" src="https://github.com/user-attachments/assets/c3694661-31e3-4be8-9a86-6eb4dd4647b5" />

Figure 16. Executing arbitrary JavaScript code

Credit

This vulnerability was discovered by Aleksey Solovev (Positive Technologies)

Affected Packages

5 total 4 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`phpoffice/phpspreadsheet`	≥ 3.0.0&&< 3.7.0	3.7.0`composer require phpoffice/phpspreadsheet:^3.7.0`
🐘Packagist	`phpoffice/phpspreadsheet`	all versions	1.29.7`composer require phpoffice/phpspreadsheet:^1.29.7`
🐘Packagist	`phpoffice/phpspreadsheet`	≥ 2.0.0&&< 2.1.6	2.1.6`composer require phpoffice/phpspreadsheet:^2.1.6`
🐘Packagist	`phpoffice/phpspreadsheet`	≥ 2.2.0&&< 2.3.5	2.3.5`composer require phpoffice/phpspreadsheet:^2.3.5`
🐘Packagist	`phpoffice/phpexcel`	all versions	No fix

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for phpoffice/phpspreadsheet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update phpoffice/phpspreadsheet to 3.7.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2024-56411 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2024-56411 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2024-56411. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

# Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header **Product**: Phpspreadsheet **Version**: version 3.6.0 **CWE-ID**: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') **CVSS vector v.3.1**: 5.4 (AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N) **CVSS vector v.4.0**: 4.8 (AV:N/AC:L/AT:N/PR:L/UI:A/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N) **Description**: the HTML page is formed without sanitizing the hyperlink base **Impact**: executing arbitrary JavaScript code in the browser **Vulnerable component**: class `PhpOffice\PhpSpreadsheet\W

O3 Security · Impact-Aware SCA

Is CVE-2024-56411 in your dependencies?

O3 Security finds CVE-2024-56411 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

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