XWiki Platform is a generic wiki platform offering runtime services for applications built on top of it. In versions prior to 14.10.4 it's possible to exploit well known parameters in XWiki URLs to perform redirection to untrusted site. This vulnerability was partially fixed in the past for XWiki 12.10.7 and 13.3RC1 but there is still the possibility to force specific URLs to skip some checks, e.g. using URLs like `http:example.com` in the parameter would allow the redirect. The issue has now been patched against all patterns that are known for performing redirects. This issue has been patched in XWiki 14.10.4 and 15.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.
https://jira.xwiki.org/browse/XWIKI-20549
https://jira.xwiki.org/browse/XWIKI-20096
https://github.com/xwiki/xwiki-platform/security/advisories/GHSA-6gvj-8vc5-8v3j
https://github.com/xwiki/xwiki-platform/commit/e4f7f68e93cb08c25632c126356d218abf192d1e