The GSpeech TTS – WordPress Text To Speech Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Comment Content in all versions up to, and including, 3.22.0 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page. This mXSS-style transform bypasses WordPress comment kses sanitization because the payload is stored using only kses-allowed tags and attributes; the malicious event handlers and style fragments become active only when the plugin's output-buffer callback rewrites the rendered HTML at request time.