PHPSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Affected versions are subject to a bypassing of a filter which allows for an XXE-attack. This in turn allows attacker to obtain contents of local files, even if error reporting is muted. This vulnerability has been addressed in release version 2.2.1. All users are advised to upgrade. There are no known workarounds for this vulnerability.
CWE-611, CWE-611