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://github.com/pypa/advisory-database/blob/main/vulns/plone/PYSEC-2021-83.yaml"