Storage disruption via unreleased Redis connections
Published Jan 8, 2026 · Updated Jan 8, 2026
Resource exhaustion in Zauberzeug NiceGUI 2.10.0 through 3.4.1 allows remote attackers to disrupt Redis-backed storage. Client.handle_disconnect clears tab_id before Client.delete uses it, so the associated RedisPersistentDict cannot be found and its client connection and pubsub subscription remain open. No authentication is required, but the application must use Redis-backed storage; exhausting Redis maxclients leaves the app running while new users lose persistent storage and Redis-dependent functions fail.
Summary
What happened
Resource exhaustion in Zauberzeug NiceGUI 2.10.0 through 3.4.1 allows remote attackers to disrupt Redis-backed storage. Client.handle_disconnect clears tab_id before Client.delete uses it, so the associated RedisPersistentDict cannot be found and its client connection and pubsub subscription remain open. No authentication is required, but the application must use Redis-backed storage; exhausting Redis maxclients leaves the app running while new users lose persistent storage and Redis-dependent functions fail.
The record
- CVE
- CVE-2026-21874
- Published
- Jan 8, 2026
- Updated
- Jan 8, 2026
- Vendor
- Zauberzeug
- Product
- NiceGUI
- Classifications
- CWE-772, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 8, 2026CVE publishedPublication date reported by the CVE source.
- Jan 8, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=>= 2.10.0, < 3.5.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream browser-tab connection-exhaustion proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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