XSS Risk in NiceGUI Python Framework Affects Multiple Versions
CVE-2026-21871

6.1MEDIUM

Key Information:

Vendor

Zauberzeug

Status
Nicegui
Vendor
CVE Published:
8 January 2026

What is CVE-2026-21871?

The NiceGUI framework, used for building Python-based user interfaces, exhibits a Cross-Site Scripting (XSS) vulnerability in versions 2.13.0 to 3.4.1. This issue arises when untrusted input is utilized in the functions ui.navigate.history.push() or ui.navigate.history.replace(). Without adequate escaping of the URL argument when rendered into JavaScript, an attacker may execute arbitrary scripts on the victim's browser. Applications should ensure that they do not pass untrusted input to these functions to mitigate this risk. The vulnerability is resolved in version 3.5.0.

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Affected Version(s)

nicegui >= 2.13.0, < 3.5.0

References

https://github.com/zauberzeug/nicegui/security/advisories...
x_refsource_CONFIRM
https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0
x_refsource_MISC

CVSS V3.1

Score:
6.1
Severity:
MEDIUM
Confidentiality:
Low
Integrity:
Low
Availability:
Low
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Changed

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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