The Mediawiki Cargo extension through version 3.9.4 contains a reflected XSS vulnerability caused by improper input neutralization during web page generation. This flaw allows attackers to inject malicious scripts that are reflected back to users, potentially leading to client-side code execution. The vulnerability is identified as CVE-2026-96876 and is classified under CWE-79. No official patch or fix details are available in the provided information.

Successful exploitation of this reflected XSS vulnerability could allow an attacker to execute arbitrary scripts in the context of the affected web application. This may lead to session hijacking, defacement, or other client-side attacks. However, no evidence of active exploitation or known exploits in the wild is reported.

Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is available, users should consider applying any recommended temporary mitigations from the vendor or limit exposure by restricting untrusted input where possible.