What is CVE-2026-21874?

CVE-2026-21874 is a medium-severity vulnerability in Zauberzeug Nicegui, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 5.3/10. Published 2026-01-08.

How severe is CVE-2026-21874?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Vulnerability in Zauberzeug Nicegui

CVE-2026-21874

NiceGUI is a Python-based UI framework. From versions v2.10.0 to 3.4.1, an unauthenticated attacker can exhaust Redis connections by repeatedly opening and closing browser tabs on any NiceGUI application using Redis-backed storage. Connect…

EPSS: 0.000 (8.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

Affected products

Zauberzeug Nicegui — versions >= 2.10.0, < 3.5.0

Weakness classification (CWE)

CWE-772 — Missing Release of Resource after Effective Lifetime

References

https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mp55-g7pj-rvm2 (x_refsource_CONFIRM)
https://github.com/zauberzeug/nicegui/commit/6c52eb2c90c4b67387c025b29646b4bc1578eb83 (x_refsource_MISC)
https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-21874?: CVE-2026-21874 is a medium-severity vulnerability in Zauberzeug Nicegui, classified under Missing Release of Resource after Effective Lifetime. CVSS score: 5.3/10. Published 2026-01-08.
How severe is CVE-2026-21874?: Medium severity. CVSS v3 base score is 5.3 out of 10.