CVE-2019-12331: Phpoffice Phpspreadsheet

High severity, CVSS 8.8. EPSS: 1.4% chance of exploitation in the next 30 days.

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.

Affected products

• Phpoffice Phpspreadsheet: before 1.8.0 (fixed in 1.8.0)

Published 2019-11-07. Last modified 2026-06-17.