Path traversal and Server-Side Request Forgery in HTML writer when embedding images is enabled in PHPSpreadsheet

Summary

PHPSpreadsheet is a pure PHP library for reading and writing spreadsheet files. It's possible for an attacker to construct an XLSX file that links images from arbitrary paths. When embedding images has been enabled in HTML writer with `$writer->setEmbedImages(true);` those files will be included in the output as `data:` URLs, regardless of the file's type. Also URLs can be used for embedding, resulting in a Server-Side Request Forgery vulnerability. When embedding images has been enabled, an attacker can read arbitrary files on the server and perform arbitrary HTTP GET requests. Note that any PHP protocol wrappers can be used, meaning that if for example the `expect://` wrapper is enabled, also remote code execution is possible. This issue has been addressed in release versions 1.29.2, 2.1.1, and 2.3.0. All users are advised to upgrade. there are no known workarounds for this vulnerability.

Timeline

1. Oct 7, 2024, 8:09 PM UTCCVE published
2. Oct 8, 2024, 6:31 PM UTCCISA SSVC assessment

   Exploitation: poc · Automatable: no · Technical impact: partial

3. Oct 8, 2024, 6:32 PM UTCRecord last updated

Affected versions

• PHPOffice PhpSpreadsheet

  fixed in 1.29.2; From 2.0.0 · fixed in 2.1.1; From 2.2.0 · fixed in 2.3.0

• phpoffice/phpspreadsheetPackagist

  From 2.2.0 · fixed in 2.3.0

• phpoffice/phpspreadsheetPackagist

  fixed in 1.29.2

• phpoffice/phpspreadsheetPackagist

  From 2.0.0 · fixed in 2.1.1

• phpoffice/phpexcelPackagist

  through 1.8.2

References 1