CKAN is an open-source DMS (data management system) for powering data hubs and data portals. Prior to 2.10.9 and 2.11.4, the helpers.markdown_extract() function did not perform sufficient sanitization of input data before wrapping in an HTML literal element. This helper is used to render user-provided data on dataset, resource, organization or group pages (plus any page provided by an extension that used that helper function), leading to a potential XSS vector. This vulnerability has been fixed in CKAN 2.10.9 and 2.11.4.
https://github.com/ckan/ckan/security/advisories/GHSA-2r4h-8jxv-w2j8
https://github.com/ckan/ckan/commit/6d0065f2fc7e2682196d125275af34b93e9e554e