CVE-2025-66645: PYSEC-2026-1700 - NiceGUI has a path traversal in app.add_media_files() allows arbitrary file read

CVE-2025-66645 · Severity: high · CVSS 7.5 · Published 2025-12-09

NiceGUI is a Python-based UI framework. Versions 3.3.1 and below are vulnerable to directory traversal through the App.add_media_files() function, which allows a remote attacker to read arbitrary files on the server filesystem. This issue is fixed in version 3.4.0.

Technologies: nicegui (PyPI). Vendors: PyPI, Zauberzeug.

Quick answers

Is CVE-2025-66645 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2025-66645 being exploited in the wild.
How severe is CVE-2025-66645?
High severity, with a CVSS score of 7.5, published 9 December 2025.
Which products and versions are affected?
nicegui (PyPI) ECOSYSTEM:introduced=0,fixed=3.4.0.
Is there a fix for CVE-2025-66645?
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-2025-66645?
Check whether you run nicegui (PyPI) or Zauberzeug Nicegui 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
  • Zauberzeug Nicegui

Identifiers

  • CVE-2025-66645
  • GHSA-hxp3-63hc-5366
  • PYSEC-2026-1700

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