CVE-2026-21874

Name: CVE-2026-21874
Creator: NVD / NIST
Published: 2026-01-08T10:15:55.82+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.51%

Last modified Jun 17, 2026

CVE-2026-21874 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. 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. EPSS estimates a 0.51% chance of exploitation in the next 30 days.

Description

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. Connections are never released, leading to service degradation when Redis hits its connection limit. NiceGUI continues accepting new connections - errors are logged but the app stays up with broken storage functionality. This issue has been patched in version 3.5.0.

Metrics

CVSS 3.1

5.3/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS Probability

0.51%

39.6th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-772

Affected Software

Vendor	Product	Versions
Zauberzeug	Nicegui	>= 2.10.0, < 3.5.0

References

https://github.com/zauberzeug/nicegui/commit/6c52eb2c90c4b67387c025b29646b4bc1578eb83Patch
https://github.com/zauberzeug/nicegui/releases/tag/v3.5.0Release Notes
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mp55-g7pj-rvm2Exploit, Vendor Advisory
https://github.com/zauberzeug/nicegui/security/advisories/GHSA-mp55-g7pj-rvm2Exploit, Vendor Advisory

Timeline

Published: Jan 8, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-21874?

How severe is CVE-2026-21874?

CVE-2026-21874 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.51% probability of exploitation in the next 30 days.

How do I fix CVE-2026-21874?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-21874?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST