CVE-2025-66469 — NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection
NiceGUI is a Python-based UI framework. Versions 3.3.1 and below are vulnerable to Reflected XSS through its ui.add_css, ui.add_scss, and ui.add_sass functions. The functions la…
Published: 2025-12-08 · CVSS: 6.1 · CVSS 3.1
NiceGUI is a Python-based UI framework. Versions 3.3.1 and below are vulnerable to Reflected XSS through its ui.add_css, ui.add_scss, and ui.add_sass functions. The functions lack proper sanitization or encoding for the JavaScript context they generate. An attacker can break out of the intended <style> or <script> tags by injecting closing tags (e.g., </style> or </script>), allowing for the execution of arbitrary JavaScript. This issue is fixed in version 3.4.0.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7