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.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/zauberzeug/nicegui/commit/a8fd25b7d5e23afb1952d0f60a1940e18b5f1ca8 Patch
- https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg Exploit, Vendor Advisory
- https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg Exploit, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.1 · zauberzeugNVD modified 2026-10-19 19:10
Affected (CPE criteria) 1
cpe:2.3:a:zauberzeug:nicegui:*:*:*:*:*:*:*:*