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

CVE-2026-21872

Medium
6.1/10

Summary

NiceGUI is a Python-based UI framework. From versions 2.22.0 through 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 Cross-Site Scripting (XSS) when the user actively clicks on the link. This issue has been patched in version 3.5.0.

  • LOW
  • NETWORK
  • LOW
  • CHANGED
  • REQUIRED
  • NONE
  • LOW
  • NONE

CWE-79 - Cross Site Scripting

Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.

References

Advisory Timeline

  • Published