CVE-2026-109299
Received Received - Intake

Authenticated DoS via Recurrence Rules in Open WebUI

Publication date: 2026-10-12

Last updated on: 2026-10-12

Assigner: VulnCheck

Description
Open WebUI from 0.9.0 before 0.11.4 contains a denial of service vulnerability that allows authenticated users with automations permission to stall the instance by submitting unsatisfiable recurrence rules. Attackers can repeatedly send rules like February 30th to the automations create or update endpoints, blocking the shared event loop for seconds per request.

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Meta Information

Published
2026-10-12
Last Modified
2026-10-12
Generated
2026-10-12
AI Q&A
2026-10-12
EPSS Evaluated
N/A
NVD
CVE-2026-109299
EUVD
EUVD-2026-97601

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
open-webui open-webui 0.9.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.

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Executive Summary

CVE-2026-109299 is a denial of service vulnerability in Open WebUI versions 0.9.0 to 0.11.3. Authenticated users with automations permissions can exploit it by submitting invalid recurrence rules like February 30th to stall the instance. The system blocks the shared event loop for seconds per request, making the instance unresponsive.

Detection Guidance

To detect this vulnerability, monitor for repeated requests to the automations create or update endpoints with invalid recurrence rules like February 30th. Check for stalled instances or unresponsive event loops during such requests. No specific commands are provided in the resources.

Impact Analysis

This vulnerability can impact you by causing your Open WebUI instance to become unresponsive or slow for all users. Attackers can repeatedly exploit it to block the event loop, leading to degraded performance or complete unavailability of the system.

Mitigation Strategies

Upgrade Open WebUI to version 0.11.4 or later to apply the patch. Alternatively, restrict automations permissions to trusted users only. Implement a timeout for recurrence rule evaluations as described in the fix.

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