PT-2025-49681 · Nicegui · Nicegui

CVE-2025-66469 · Published 2025-12-08 · Updated 2026-07-07

Positive Technologies (AI Summary)

CVSS v3.1

6.1

Medium

Base vector

AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Name of the Vulnerable Software and Affected Versions NiceGUI versions 3.3.1 and below

Description NiceGUI, a Python-based UI framework, has an issue where the ui.add css, ui.add scss, and ui.add sass functions do not properly sanitize or encode JavaScript contexts. This allows an attacker to inject closing tags, such as or , to break out of intended tags and execute arbitrary JavaScript. The functions are vulnerable due to a lack of proper sanitization or encoding.

Recommendations Update to version 3.4.0 or later.

Exploit

Fix

XSS

Weakness Enumeration

CWE-79

Related Identifiers

CVE-2025-66469

GHSA-72QC-WXCH-74MG

PYSEC-2026-1697

Affected Products

Nicegui

References · 13

• 🔥 https://github.com/zauberzeug/nicegui/security/advisories/GHSA-72qc-wxch-74mg · Exploit
• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/66xxx/CVE-2025-66469.json · Exploit
• https://github.com/zauberzeug/nicegui/commit/a8fd25b7d5e23afb1952d0f60a1940e18b5f1ca8 · Patch
• https://osv.dev/vulnerability/CVE-2025-66469 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2025-66469 · Security Note
• https://osv.dev/vulnerability/PYSEC-2026-1697 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-72qc-wxch-74mg · Vendor Advisory
• https://github.com/zauberzeug/nicegui · Note
• https://github.com/advisories/GHSA-72qc-wxch-74mg · Note
• https://twitter.com/CVEnew/status/2003234000337535284 · Twitter Post
• https://pypi.org/project/nicegui · Note
• https://t.me/CVEtracker/39179 · Telegram Post
• https://twitter.com/dailycve/status/1999168313608319040 · Twitter Post