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Description

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.

PUBLISHED Reserved 2026-01-05 | Published 2026-01-08 | Updated 2026-01-08 | Assigner GitHub_M




MEDIUM: 6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Problem types

CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Product status

>= 2.13.0, < 3.5.0
affected

References

github.com/...icegui/security/advisories/GHSA-7grm-h62g-5m97

github.com/zauberzeug/nicegui/releases/tag/v3.5.0

cve.org (CVE-2026-21871)

nvd.nist.gov (CVE-2026-21871)

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