CVE-2025-66469
NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection
- State
- Published
- Severity
- 6.1 Medium
- Published
- Dec 8, 2025
- Updated
- Dec 9, 2025
- Reserved
- Dec 2, 2025
Description
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 6.1 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N | GitHub_M |
Weaknesses
- CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Products
| Product | Versions |
|---|---|
niceguizauberzeug |
|
References
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