CVE-2026-21874
published 2026-01-08CVE-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…
PriorityP431medium5.3CVSS 3.1
AVNACLPRNUINSUCNINAL
EPSS
0.51%
39.6th percentile
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.
Affected
3 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| zauberzeug | nicegui | — | — |
| zauberzeug | nicegui | >= 2.10.0 < 3.5.0 | 3.5.0 |
| zauberzeug | nicegui | >= 2.10.0 < 3.5.0 | 3.5.0 |
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GHSA
NiceGUI has Redis connection leak via tab storage causes service degradation
ghsa·2026-01-08
CVE-2026-21874 [MEDIUM] CWE-772 NiceGUI has Redis connection leak via tab storage causes service degradation
NiceGUI has Redis connection leak via tab storage causes service degradation
### Summary
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.**
### Details
When a client disconnects, tab_id is cleared at https://github.com/zauberzeug/nicegui/blob/main/nicegui/client.py#L307 before delete() is called at https://github.com/zauberzeug/nicegui/blob/main/nicegui/client.py#L319. By then tab_id is None, so there's no way to find the RedisPersistentDict and call https://g
OSV
NiceGUI has Redis connection leak via tab storage causes service degradation
osv·2026-01-08
CVE-2026-21874 [MEDIUM] NiceGUI has Redis connection leak via tab storage causes service degradation
NiceGUI has Redis connection leak via tab storage causes service degradation
### Summary
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.**
### Details
When a client disconnects, tab_id is cleared at https://github.com/zauberzeug/nicegui/blob/main/nicegui/client.py#L307 before delete() is called at https://github.com/zauberzeug/nicegui/blob/main/nicegui/client.py#L319. By then tab_id is None, so there's no way to find the RedisPersistentDict and call https://g
No detection rules found.
No public exploits indexed.
2026-01-08
Published