CVE-2026-21874 – NiceGUI has Redis connection leak via tab storage causes service degradation

CVE ID : CVE-2026-21874

Published : Jan. 8, 2026, 9:50 a.m. | 37 minutes ago

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.

Severity: 0.0 | NA

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