NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do despite being cross-site, using an iframe. This issue has been patched in version 3.5.0.
History

Fri, 09 Jan 2026 13:30:00 +0000

Type Values Removed Values Added
First Time appeared Zauberzeug
Zauberzeug nicegui
Vendors & Products Zauberzeug
Zauberzeug nicegui

Thu, 08 Jan 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 08 Jan 2026 10:00:00 +0000

Type Values Removed Values Added
Description NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do despite being cross-site, using an iframe. This issue has been patched in version 3.5.0.
Title Zero-click XSS in all NiceGUI apps which uses `ui.sub_pages`
Weaknesses CWE-79
References
Metrics cvssV3_1

{'score': 7.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-01-08T15:11:24.092Z

Reserved: 2026-01-05T16:44:16.369Z

Link: CVE-2026-21873

cve-icon Vulnrichment

Updated: 2026-01-08T15:11:18.086Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-01-08T10:15:55.617

Modified: 2026-01-08T18:08:18.457

Link: CVE-2026-21873

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-01-09T13:25:32Z