Vulnerability · Published Jan 8, 2026 · Assigned by GitHub_M
CVE-2026-21874NiceGUI has Redis connection leak via tab storage causes service degradation
Medium 5.3
In plain English
A medium-severity security flaw in nicegui from zauberzeug. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 46% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | nicegui | 3.5.0 | GHSA-mp55-g7pj-rvm2 |
| PyPI | nicegui | 3.5.0 | PYSEC-2026-1703 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| zauberzeug | nicegui | >= 2.10.0, < 3.5.0 |
Weakness: CWE-772 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L