Stored XSS occurs when attacker-controlled input is saved by an application and later rendered in other users ' browsers as executable script. Because the scenario explicitly identifies missing output encoding as the weakness, the primary remediation is context-appropriate output encoding before displaying untrusted content. ECIH v3 web-application incident handling emphasizes correcting the underlying application vulnerability rather than relying only on perimeter controls. Proper encoding causes characters with executable significance to be rendered as data instead of browser-interpreted markup or JavaScript. Multi-factor authentication protects accounts but does not prevent XSS. Updating the CMS and plugins is good security hygiene but will not correct custom output-handling flaws. A WAF can provide supplementary detection or blocking, but it should not replace secure application coding. Therefore, proper output encoding directly addresses the root cause.

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