Open WebUI 0.9.0 before 0.11.4 Denial of Service via Recurrence Rule Validation

{
  "id": "3214e7889a47b6a862b0592d4e13e22b9bb98f679f667272e1e1d43801103f5a",
  "url": "https://osv.dev/vulnerability/CVE-2026-109299",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Open WebUI 0.9.0 before 0.11.4 Denial of Service via Recurrence Rule Validation",
    "summary": "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.",
    "evidence": "osv:CVE-2026-109299",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-109299",
      "aliases": [
        "CVE-2026-109299",
        "GHSA-5w58-mwmh-vf2m"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/open-webui/open-webui",
              "type": "GIT",
              "events": [
                {
                  "introduced": "f31768e20e5c6b4f6da0ef657877298b359936cf"
                },
                {
                  "fixed": "8bd8b4fac5e059578ac0c74b3c18d11139f88b7d"
                },
                {
                  "fixed": "5fb869db221d9599a576e8e2eea9c3314947d25e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.9.0"
                      },
                      {
                        "fixed": "0.11.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "5fb869db221d9599a576e8e2eea9c3314947d25e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.11.3",
            "v0.11.2",
            "v0.11.1",
            "v0.11.0",
            "v0.10.2",
            "v0.10.1",
            "v0.10.0",
            "v0.9.5",
            "v0.9.4",
            "v0.9.3",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109299.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.985087464Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109299.json",
        "https://github.com/open-webui/open-webui/security/advisories/GHSA-5w58-mwmh-vf2m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-109299",
        "https://www.vulncheck.com/advisories/open-webui-0.9.0-before-0.11.4-denial-of-service-via-recurrence-rule-validation",
        "https://github.com/open-webui/open-webui/commit/5fb869db221d9599a576e8e2eea9c3314947d25e"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-400",
          "CWE-834"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109299.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-109299",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 518548,
  "published_at": "2026-10-12T16:04:57.527+00:00"
}