An issue was discovered in Joomla! 3.0.0 through 3.9.26. HTML was missing in the executable block list of MediaHelper::canUpload, leading to XSS attack vectors.Referenceshttps://developer.joomla.org/security-centre/852-20210501-core-adding-html-to-the-executable-block-list-of-mediahelper-canupload.html
