XSS in Zauberzeug Nicegui
CVE-2026-21873
NiceGUI is a Python-based UI framework. From versions 2.22.0 to 3.4.1, an unsafe implementation in the pushstate event listener used by ui.sub_pages allows an attacker to manipulate the fragment identifier of the URL, which they can do des…
Vulnerability class: XSS (Cross-Site Scripting)
EPSS: 0.002 (14.3th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 7.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N.
Affected products
- Zauberzeug Nicegui — versions >= 2.22.0, < 3.5.0
Weakness classification (CWE)
References
- security-advisories@github.com (x_refsource_CONFIRM, Exploit, Vendor Advisory)
- security-advisories@github.com (x_refsource_MISC, Release Notes)
Frequently asked questions
- What is CVE-2026-21873?
- CVE-2026-21873 is a high-severity vulnerability in Zauberzeug Nicegui, classified under Cross-site Scripting. CVSS score: 7.2/10. Published 2026-01-08.
- How severe is CVE-2026-21873?
- High severity. CVSS v3 base score is 7.2 out of 10.