What’s Vulnerable › Vulnerabilities

CVE-2026-25732: NiceGUI's Path Traversal via Unsanitized FileUpload.name Enables Arbitrary File Write

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.4% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-02-06 · updated 2026-06-17
• Weakness: CWE-22

Description

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.

Affected products

• zauberzeug nicegui: before 3.7.0 — fixed in 3.7.0

How to fix

Upgrade to a fixed version: zauberzeug nicegui 3.7.0. Check the vendor advisory for mitigations.

References

• https://github.com/zauberzeug/nicegui/blob/main/nicegui/elements/upload_files.py#L110-L115
• https://github.com/zauberzeug/nicegui/blob/main/nicegui/elements/upload_files.py#L79-L82
• https://github.com/zauberzeug/nicegui/security/advisories/GHSA-9ffm-fxg3-xrhh

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