Cross-site Scripting (XSS) Affecting phpoffice/phpexcel package, versions >=0.0.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PHP-PHPOFFICEPHPEXCEL-9299814
- published7 Mar 2025
- disclosed19 Nov 2020
- creditNikkolai Fernandez
Introduced: 19 Nov 2020
CVE-2020-7776 (opens in a new tab)How to fix?
There is no fixed version for phpoffice/phpexcel.
Overview
Affected versions of this package are vulnerable to Cross-site Scripting (XSS). The library is vulnerable to XSS when creating an html output from an excel file by adding a comment on any cell. The root cause of this issue is within the HTML writer where user comments are concatenated as part of link and this is returned as HTML.
PoC
1. Setup a project folder on your local web server 2. Open project folder in terminal to run `composer require phpoffice/phpspreadsheet` 3. Create an excel file -> Insert Comment -> Insert this payload `<script>alert(1)</script>` 4. Move the excel file to the project dir 5. Create a php file with filename `convert-excel-to-html.php` -> Insert code below<?php require './vendor/autoload.php'; use PhpOffice\PhpSpreadsheet\IOFactory;
$filename = 'INSERT_YOUR_EXCEL_FILE_HERE';
$spreadsheet = IOFactory::load('./'.$filename);
$writer = IOFactory::createWriter($spreadsheet, 'Html');
$filename = 'testxss.html'; $writer->save($filename);