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

> Authenticated users with automation permissions can cause denial of service by submitting invalid recurrence rules that block the event loop.

- **Severity:** High 7.1 (`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`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 12 Oct 2026
- **Updated:** 23 Oct 2026
- **Also known as:** GHSA-5w58-mwmh-vf2m, GHSA-vp3m-gw6c-whgh

## What is CVE-2026-109299?

CVE-2026-109299 is a high-severity denial of service vulnerability in open-webui, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official 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.

Weakness: CWE-834 (Excessive Iteration), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-109299?


## How do I fix CVE-2026-109299?

No fix has been published for CVE-2026-109299 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-109299 being exploited?

There is no known exploitation of CVE-2026-109299 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-109299 and fix it if it is affected.

What it is: CVE-2026-109299 is a high-severity denial of service vulnerability in open-webui, published on 12 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-109299 in the wild and no public exploit code.

Affected product: open-webui. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-109299/ (Markdown: https://insights.sbomify.com/CVE-2026-109299/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-109299
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-109299
- OSV: https://osv.dev/vulnerability/CVE-2026-109299

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-109299/
Summaries are generated and may contain mistakes; the official description above is the record.