EUVD-2026-208925

fkie_cve-2024-56411

PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. Versions prior to 3.7.0, 2.3.5, 2.1.6, and 1.29.7 have a cross-site scripting (XSS) vulnerability of the hyperlink base in the HTML page header. The HTML page is formed without sanitizing the hyperlink base. Versions 3.7.0, 2.3.5, 2.1.6, and 1.29.7 contain a patch for the issue.

GHSA-hwcp-2h35-p66w — PhpSpreadsheet has a Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header

Affected: Packagist: phpoffice/phpspreadsheet, Packagist: phpoffice/phpexcel

# 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…

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GHSA-hwcp-2h35-p66w — PhpSpreadsheet has a Cross-Site Scripting (XSS) vulnerability of the hyperlink base in the HTML page header