CVE-2025-66469: PYSEC-2026-1697 - NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection

CVE-2025-66469 · Severity: low · CVSS 3.1 · Published 2026-07-07

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

Technologies: nicegui (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2025-66469 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-66469 being exploited in the wild.
How severe is CVE-2025-66469?
Low severity, with a CVSS score of 3.1, published 7 July 2026.
Which products and versions are affected?
nicegui (PyPI) ECOSYSTEM:introduced=0,fixed=3.4.0.
Is there a fix for CVE-2025-66469?
Yes. nicegui (PyPI): upgrade to 3.4.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2025-66469?
Check whether you run nicegui (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • nicegui (PyPI): upgrade to 3.4.0 or later
    pip install "nicegui>=3.4.0"

Affected products

  • nicegui (PyPI) ECOSYSTEM:introduced=0,fixed=3.4.0

Identifiers

  • CVE-2025-66469
  • GHSA-72qc-wxch-74mg
  • PYSEC-2026-1697

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