In October from version 1.0.319 and before version 1.0.466, a user with access to a markdown FormWidget that stores data persistently could create a stored XSS attack against themselves and any other users with access to the generated HTML from the field. This has been fixed in 1.0.466. For users of the RainLab.Blog plugin, this has also been fixed in 1.4.1.
packetstormsecurity.com/files/158730/October-CMS-Build-465-XSS-File-Read-File-Deletion-CSV-Injection.html
seclists.org/fulldisclosure/2020/Aug/2
github.com/octobercms/october/commit/9ecfb4867baae14a0d3f99f5b5c1e8a979ae8746
github.com/octobercms/october/security/advisories/GHSA-w4pj-7p68-3vgv
github.com/rainlab/blog-plugin/commit/6ae19a6e16ef3ba730692bc899851342c858bb94