Plone though 5.2.4 allows SSRF via the lxml parser. This affects Diazo themes, Dexterity TTW schemas, and modeleditors in plone.app.theming, plone.app.dexterity, and plone.supermodel.
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-33511.json"