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

Source: https://junglewise.ai/threats/cve-2025-66645-nicegui-has-a-path-traversal-in-app-add-media-files-allows  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-12-09  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/nicegui). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi), [Zauberzeug](https://junglewise.ai/threats/vendors/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

  ```sh
  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

## Related threats

- [PYSEC-2026-1703 - NiceGUI has Redis connection leak via tab storage causes service degradation](https://junglewise.ai/threats/cve-2026-21874-nicegui-has-redis-connection-leak-via-tab-storage-causes-service)
- [PYSEC-2026-1702 - NiceGUI apps which use `ui.sub_pages` vulnerable to zero-click XSS](https://junglewise.ai/threats/cve-2026-21873-nicegui-apps-which-use-ui-sub-pages-vulnerable-to-zero-click-xss)
- [PYSEC-2026-1701 - NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links](https://junglewise.ai/threats/cve-2026-21872-nicegui-apps-are-vulnerable-to-xss-which-uses-ui-sub-pages-and)
- [PYSEC-2026-1698 - NiceGUI is vulnerable to XSS via Unescaped URL in ui.navigate.history.push() / replace()](https://junglewise.ai/threats/cve-2026-21871-nicegui-is-vulnerable-to-xss-via-unescaped-url-in-ui-navigate)
- [PYSEC-2026-1697 - NiceGUI Reflected XSS in ui.add_css, ui.add_scss, and ui.add_sass via Style Injection](https://junglewise.ai/threats/cve-2025-66469-nicegui-reflected-xss-in-ui-add-css-ui-add-scss-and-ui-add-sass)