CVE-2025-66469CWE-79cross-site-scripting

CVE-2025-66469

Medium · published December 9, 2025

CVSS v3.1
6.1
EPSS
0%
Percentile
18.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.1 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CVSS v4.0
Not supplied
EPSS
0.00275 · 18.8th percentile
Weakness
CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Published
2025-12-09T05:15Z
Affected products (1)
ProductVersionsFixed in
zauberzeug/nicegui< 3.4.03.4.0
References (3)
https://github.com/zauberzeug/nicegui/commit/a8fd25b7d5e23afb1952d0f60a1940e18b5f1ca8 · [email protected]https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg · [email protected]https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 08 DEC 23:54Z
    NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection
    cvelistv5