ObjectPlanet Opinio before 7.15 allows XXE attacks via three steps: modify a .css file to have <!ENTITY content, create a .xml file for a generic survey template (containing a link to this .css file), and import this .xml file at the survey/admin/folderSurvey.do?action=viewImportSurvey['importFile'] URI. The XXE can then be triggered at a admin/preview.do?action=previewSurvey&surveyId= URI.

References

• https://nvd.nist.gov/vuln/detail/CVE-2020-26564
• https://packetstormsecurity.com/files/163707/ObjectPlanet-Opinio-7.13-7.14-XML-Injection.html
• https://www.objectplanet.com/opinio/changelog.html