Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)

{
  "id": "15791b4780a4c0dda8396c76e18c4ecd6afdb8450caa949b859fa55b428610b7",
  "url": "https://osv.dev/vulnerability/CVE-2026-59714",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Open WebUI: Cross-channel message overwrite via chat completion API (single-model and multimodel message_ids)",
    "summary": "Open WebUI is an extensible, feature-rich, and user-friendly self-hosted AI platform. From 0.9.5 before 0.10.0, any authenticated user can overwrite the content of a message in a channel they do not belong to (including private and DM channels) by sending a chat completion request with a channel:-prefixed chat_id and a target message_id. The channel: path routes pipeline output through _make_channel_emitter, which writes to the Messages table using the caller-supplied message_id without binding it to the channel. This issue is fixed in version 0.10.0.",
    "evidence": "osv:CVE-2026-59714",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-59714",
      "aliases": [
        "CVE-2026-59714",
        "GHSA-x2ff-v5v8-m75m",
        "PYSEC-2026-3605"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/open-webui/open-webui",
              "type": "GIT",
              "events": [
                {
                  "introduced": "3660bc00fd807deced3400a63bfa6db47811a3bb"
                },
                {
                  "fixed": "4d2e13cf2bcc451b33bb6374bea4d2163e6cc94c"
                },
                {
                  "fixed": "ac3449cac91e62b08a7c28e54fcd044d14dea791"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.9.5"
                      },
                      {
                        "fixed": "0.10.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "ac3449cac91e62b08a7c28e54fcd044d14dea791"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4d2e13cf2bcc451b33bb6374bea4d2163e6cc94c"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.10.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.9.5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59714.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:36.207747888Z",
      "provider": "osv",
      "references": [
        "https://github.com/open-webui/open-webui/releases/tag/v0.10.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59714.json",
        "https://github.com/open-webui/open-webui/security/advisories/GHSA-x2ff-v5v8-m75m",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-59714",
        "https://github.com/open-webui/open-webui/commit/ac3449cac91e62b08a7c28e54fcd044d14dea791",
        "https://github.com/open-webui/open-webui/pull/26385"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-862"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59714.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-59714",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 503384,
  "published_at": "2026-08-13T19:10:42.122+00:00"
}