CVE-2026-25732
NiceGUI's Path Traversal via Unsanitized FileUpload.name Enables Arbitrary File Write
- Published
- Feb 6, 2026
- Updated
- Feb 9, 2026
- Assigning CNA
- GitHub_M
- Evidence observed
- Apr 30, 2026
Primary CVSS
nvd · CVSS 3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:NLow · next 30 days
- Percentile
- 88.1%
- Model date
- Sep 21, 2026
EPSS is a statistical estimate, not a certainty or a measure of impact. Combine it with CVSS, KEV status, exposure and your environment.
Summary
NiceGUI is a Python-based UI framework. Prior to 3.7.0, NiceGUI's FileUpload.name property exposes client-supplied filename metadata without sanitization, enabling path traversal when developers use the pattern UPLOAD_DIR / file.name. Malicious filenames containing ../ sequences allow attackers to write files outside intended directories, with potential for remote code execution through application file overwrites in vulnerable deployment patterns. This design creates a prevalent security footgun affecting applications following common community patterns. Note: Exploitation requires application code incorporating file.name into filesystem paths without sanitization. Applications using fixed paths, generated filenames, or explicit sanitization are not affected. This vulnerability is fixed in 3.7.0.
Sources
2- CVE-2026-25732-NiceGUI-3.6.1Exploit
Exploit for CVE-2026-25732, a path traversal in NiceGUI's FileUpload that allows unauthenticated arbitrary file write. Includes usage examples for overwriting application files or dropping webshells.
Responsible use
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