VYPR
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Moderate severityNVD Advisory· Published Dec 8, 2025· Updated Dec 9, 2025

NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection

CVE-2025-66469

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.

AI Insight

LLM-synthesized narrative grounded in this CVE's description and references.

Affected packages

Versions sourced from the GitHub Security Advisory.

PackageAffected versionsPatched versions
niceguiPyPI
< 3.4.03.4.0

Affected products

2

Patches

Vulnerability mechanics

References

4

News mentions

0

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