CVSS 3.1
6.1 mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NCVE-2026-21871
Medium (6.1) in zauberzeug nicegui. EPSS 0.3% chance of exploitation in the next 30 days. Fixed in nicegui 3.5.0.
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.
Severity
- EPSS
- 0.3% chance of exploitation in the next 30 days; higher than 19% of CVEs (scores of 2026-10-31)
- CWE
- CWE-79
- Published
- Modified
- Record from
- the NVD, synced
Affected
- zauberzeug:nicegui
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-7grm-h62g-5m97 | PyPI | nicegui | >=2.13.0 <3.5.0 | 3.5.0 |
| PYSEC-2026-1698 | PyPI | nicegui | >=2.13.0 <3.5.0 | 3.5.0 |