CVE-2026-109297 open-webui CVE debrief

Who should care

Defenders responsible for Open WebUI deployments, especially those using versions 0.11.0 to 0.11.3, should assess exposure and prioritize verification and mitigation of this vulnerability.

Why it matters

Defenders should care about CVE-2026-109297 because it allows users with automation creation permissions to submit malicious rules that can block the shared event loop, leading to denial of service. Affected Open WebUI deployments (versions 0.11.0 to 0.11.3) should verify exposure and prioritize remediation.

• Blocking of the shared event loop for minutes per request and on every scheduler poll, leading to denial of service.
• Potential for exploitation by users with permission to create automations.
• Need for verification of Open WebUI version and exposure.
• Prioritization of remediation efforts for affected systems.

Technical summary

The automation recurrence-rule validator in Open WebUI 0.11.0 before 0.11.4 has a denial of service vulnerability. Users with permission to create automations can submit malicious rules that cause the shared event loop to block for minutes per request and on every scheduler poll. The vulnerability is due to the validator's strict parsing of rule text, which can be exploited by users with automation creation permissions. Affected Open WebUI deployments should verify exposure and prioritize remediation efforts. The CVE record and source item provide details on the denial of service vulnerability in Open WebUI 0.11.0 before 0.11.4.

Defensive priority

Defenders should prioritize verifying exposure and assessing the impact of this vulnerability on their systems, especially those using Open WebUI versions 0.11.0 to 0.11.3.

Recommended defensive actions

• Verify Open WebUI version and check if it's within the affected range (0.11.0 to 0.11.3).
• Assess the impact of the denial of service vulnerability on systems using Open WebUI.
• Implement compensating controls to mitigate the vulnerability, such as limiting automation creation to trusted users.
• Monitor system performance and event logs for potential exploitation attempts.
• Review relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.

Evidence notes

The CVE record and source item provide details on the denial of service vulnerability in Open WebUI 0.11.0 before 0.11.4. However, the corpus does not establish versions, exploitation, impact, or remediation beyond vendor advisories.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.