Medium 6.1Published Jan 8, 2026

CVE-2026-21871NiceGUI is a Python-based UI framework.

Updated under an hour ago (2026-10-19 07:00 UTC)

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No exploitation reported and no EPSS estimate yet.

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Every CVE for zauberzeug nicegui

Exploited in the last 30 days

NiceGUI is a Python-based UI framework. From versions 2.13.0 to 3.4.1, there is a XSS risk in NiceGUI when developers pass attacker-controlled strings into ui.navigate.history.push() or ui.navigate.history.replace(). These helpers are documented as History API wrappers for updating the browser URL without page reload. However, if the URL argument is embedded into generated JavaScript without proper escaping, a crafted payload can break out of the intended string context and execute arbitrary JavaScript in the victim’s browser. Applications that do not pass untrusted input into ui.navigate.history.push/replace are not affected. This issue has been patched in version 3.5.0.

CVSS: 6.1 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Weakness (CWE): CWE-79
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: Not given
NVD analysis: Analyzed
Record last updated: Jun 17, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

zauberzeug nicegui zauberzeug:nicegui	from 2.13.0 before 3.5.0	NVD

References

https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0release-notes
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-7grm-h62g-5m97exploit, vendor-advisory

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.