Vulnerabilities > CVE-2019-12331 - XXE vulnerability in PHPoffice PHPspreadsheet
Attack vector
NETWORK Attack complexity
LOW Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
HIGH Summary
PHPOffice PhpSpreadsheet before 1.8.0 has an XXE issue. The XmlScanner decodes the sheet1.xml from an .xlsx to utf-8 if something else than UTF-8 is declared in the header. This was a security measurement to prevent CVE-2018-19277 but the fix is not sufficient. By double-encoding the the xml payload to utf-7 it is possible to bypass the check for the string ‚<!ENTITY‘ and thus allowing for an xml external entity processing (XXE) attack.