CVE-2024-48917 Information

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 in a bypass of the previously reported CVE-2024-47873 the regexes from the findCharSet method which is used for determining the current encoding can be bypassed by using a payload in the encoding UTF-7 and adding at end of the file a comment with the value encoding=TF-8\ with \ which is matched by the first regex so that encoding='UTF-7' with single quotes ' in the XML header is not matched by the second regex. 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.

Reference

https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-7cc9-j4mv-vcjp https://github.com/PHPOffice/PhpSpreadsheet/blob/39fc51309181e82593b06e2fa8e45ef8333a0335/src/PhpSpreadsheet/Reader/Security/XmlScanner.php https://owasp.org/www-community/vulnerabilities/XML_External_Entity_(XXE)_Processing