CVE-2025-66469

PoC —

CVSS 3.1

6.1 medium

EPSS

<1%p20

Published

Dec 9, 2025 (Dec 9, 2025)

Modified

Jun 17, 2026

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 or ), allowing for the execution of arbitrary JavaScript. This issue is fixed in version 3.4.0.

Vendors: zauberzeug
Products: nicegui
Weakness: CWE-79
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

NVD CVE.org GitHub PoCs EPSS (0.3%)

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