CVE-2026-74793 describes a cross-site scripting vulnerability in EmilStenstrom's justhtml software before version 3.11.0. The issue arises because the default sanitizer bypasses removal of event handlers in selectedcontent projections. Attackers can exploit this by injecting SVG or MathML elements containing event handlers that are cloned and reinserted into the output without proper sanitization, leading to stored or reflected XSS attacks. This vulnerability allows execution of arbitrary scripts in the context of the affected web application.

Successful exploitation of this vulnerability can lead to execution of arbitrary scripts in users' browsers, potentially resulting in session hijacking, defacement, or redirection to malicious sites. The CVSS score of 5.1 indicates a medium severity impact. There is no indication of known exploits in the wild at this time.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider applying additional input sanitization or filtering measures to mitigate injection of malicious SVG or MathML elements with event handlers. Monitor vendor communications for updates on patches or official mitigations.