Moderate severityOSV Advisory· Published Jan 8, 2026· Updated Jan 8, 2026
NiceGUI apps are vulnerable to XSS which uses `ui.sub_pages` and render arbitrary user-provided links
CVE-2026-21872
Description
NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the click event listener used by ui.sub_pages, combined with attacker-controlled link rendering on the page, causes XSS when the user actively clicks on the link. This issue has been patched in version 3.5.0.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
niceguiPyPI | >= 2.22.0, < 3.5.0 | 3.5.0 |
Affected products
1- Range: v2.22.0, v2.22.1, v2.23.0, …
Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
4- github.com/advisories/GHSA-m7j5-rq9j-6jj9ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-21872ghsaADVISORY
- github.com/zauberzeug/nicegui/releases/tag/v3.5.0ghsax_refsource_MISCWEB
- github.com/zauberzeug/nicegui/security/advisories/GHSA-m7j5-rq9j-6jj9ghsax_refsource_CONFIRMWEB
News mentions
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