CVE-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 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.

CVSS v3.1

5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS v3.1

5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

0.53% chance of exploitation in the next 30 days, 43th percentile

Published

2026-01-08

Proof-of-concept exploits (1)

• advisories/GHSA-mp55-g7pj-rvm2

References

• CVE Record
• NVD entry

Related

• CVE-2026-21873
• CVE-2026-21876
• CVE-2026-21872
• CVE-2026-21877
• CVE-2026-21871
• CVE-2026-2188