ASA-2019-00512 – Apache HTTP Server: Limited Cross-Site Scripting (XSS) in mod_proxy error page

A limited Cross-Site Scripting (XSS) issue was reported affecting the mod_proxy error page. An attacker could cause the link on the error page to be malformed and instead point to a page of their choice. This would only be exploitable where a server was set up with proxying enabled but was misconfigured in such a way that the Proxy Error page was displayed.