CVE-2026-39844

NiceGUI is a Python-based UI framework. Prior to 3.10.0, Since PurePosixPath only recognizes forward slashes (/) as path separators, an attacker can bypass this sanitization on Windows by using backslashes (\) in the upload filename. Applications that construct file paths using file.name (a pattern demonstrated in NiceGUI's bundled examples) are vulnerable to arbitrary file write on Windows. This vulnerability is fixed in 3.10.0.

CVSS v3 5.9 MEDIUM

5.9^/10

CVSS v3 : MEDIUM

Vector :

Exploitability : 2.2 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact HIGH

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/zauberzeug/nicegui/commit/d38a702e3af2da5b0708f689be8d71413fc77056	Patch
https://github.com/zauberzeug/nicegui/releases/tag/v3.10.0	Release Notes
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-w8wv-vfpc-hw2w	Vendor Advisory

Configurations

Configuration 1 (hide)

AND

cpe:2.3:a:zauberzeug:nicegui:*:*:*:*:*:*:*:*

cpe:2.3:o:microsoft:windows:-:*:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-08 21:16

Updated : 2026-07-24 21:10

NVD link : CVE-2026-39844

Mitre link : CVE-2026-39844

CVE.ORG link : CVE-2026-39844

JSON object : View

Products Affected

zauberzeug

nicegui

microsoft

windows

CWE

CWE-22

Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

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