CVE-2026-21873

PoC —

CVSS 3.1

6.1 medium

EPSS

<1%p18

Published

Jan 8, 2026 (Jan 8, 2026)

Modified

Jun 17, 2026

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.

Vendors: zauberzeug
Products: nicegui
Weakness: CWE-79
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

NVD CVE.org GitHub PoCs EPSS (0.3%)

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