Description
PhpSpreadsheet is a PHP library for reading and writing spreadsheet files. The XmlScanner class has a scan method which should prevent XXE attacks. However, prior to versions 1.9.4, 2.1.3, 2.3.2, and 3.4.0, the regexes used in the `scan` method and the findCharSet method can be bypassed by using UCS-4 and encoding guessing. An attacker can bypass the sanitizer and achieve an XML external entity attack. Versions 1.9.4, 2.1.3, 2.3.2, and 3.4.0 fix the issue.
CVSS breakdown
CVSS 3.1
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Affected products
- PHPOffice / PhpSpreadsheet< 1.29.4 – < 1.29.4
- PHPOffice / PhpSpreadsheet>= 2.0.0, < 2.1.3 – >= 2.0.0, < 2.1.3
- PHPOffice / PhpSpreadsheet>= 2.2.0, < 2.3.2 – >= 2.2.0, < 2.3.2
- PHPOffice / PhpSpreadsheet>= 3.3.0, < 3.4.0 – >= 3.3.0, < 3.4.0
References
- VENDOR_ADVISORYhttps://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-jw4x-v69f-hh5w
- MISChttps://github.com/PHPOffice/PhpSpreadsheet/blob/39fc51309181e82593b06e2fa8e45ef8333a0335/src/PhpSpreadsheet/Reader/Security/XmlScanner.php
- MISChttps://owasp.org/www-community/vulnerabilities/XML_External_Entity_(XXE)_Processing
- MISChttps://www.w3.org/TR/xml/#sec-guessing-no-ext-info