CVE-2026-21874CWE-772

NiceGUI has Redis connection leak via tab storage causes service degradation

Medium · published January 8, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
45.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00554 · 45.5th percentile
Weakness
CWE-772 · Missing Release of Resource after Effective Lifetime
Published
2026-01-08T09:50Z
EPSS history
Timeline
  • 08 JAN 09:50Z
    NiceGUI has Redis connection leak via tab storage causes service degradation
    cvelistv5