When using default XWiki configuration, it’s possible for an attacker to upload an SVG containing a script executed when executing the download action on the file.
This problem has been patched so that the default configuration doesn’t allow to display the SVG files in the browser.
This issue can be fixed without the patch by setting properly the configuration to download or display files, see: https://www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Attachments#HAttachmentdisplayordownload
https://jira.xwiki.org/browse/XWIKI-18368
If you have any questions or comments about this advisory:
github.com/xwiki/xwiki-platform
github.com/xwiki/xwiki-platform/commit/5853d492b3a274db0d94d560e2a5ea988a271c62
github.com/xwiki/xwiki-platform/security/advisories/GHSA-9jq9-c2cv-pcrj
jira.xwiki.org/browse/XWIKI-18368
nvd.nist.gov/vuln/detail/CVE-2021-43841
www.xwiki.org/xwiki/bin/view/Documentation/AdminGuide/Attachments#HAttachmentdisplayordownload