Auth bypass in Zauberzeug Nicegui

CVE-2025-21618

NiceGUI is an easy-to-use, Python-based UI framework. Prior to 2.9.1, authenticating with NiceGUI logged in the user for all browsers, including browsers in incognito mode. This vulnerability is fixed in 2.9.1.

Vulnerability class: Broken Authentication

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.

EPSS exploit prediction

EPSS: 0.004 (29.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 30th percentile — 29.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-21618: held from 0.004 to 0.004.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-21618?
CVE-2025-21618 is a high-severity vulnerability in Zauberzeug Nicegui, classified under Improper Authentication. CVSS score: 7.5/10. Published 2025-01-06.
How severe is CVE-2025-21618?
High severity. CVSS v3 base score is 7.5 out of 10.