CVE-2026-21874 — NiceGUI has Redis connection leak via tab storage causes service degradation
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 …
Published: 2026-01-08 · CVSS: 5.3 · CVSS 3.1
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.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7