LibreChat's IDOR in SSE Stream Subscription Allows Reading Other Users' Chats

{
  "id": "9463d2bdb90c2f52d396766ec63cbf8b3656e292d9738de28198f8b5e0a5b05c",
  "url": "https://osv.dev/vulnerability/CVE-2026-31950",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "LibreChat's IDOR in SSE Stream Subscription Allows Reading Other Users' Chats",
    "summary": "LibreChat is a ChatGPT clone with additional features. In versions 0.8.2-rc2 through 0.8.2-rc3, the SSE streaming endpoint `/api/agents/chat/stream/:streamId` does not verify that the requesting user owns the stream. Any authenticated user who obtains or guesses a valid stream ID can subscribe and read another user's real-time chat content, including messages, AI responses, and tool invocations. Version 0.8.2 patches the issue.",
    "evidence": "osv:CVE-2026-31950",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-31950",
      "aliases": [
        "CVE-2026-31950",
        "GHSA-f6rf-vm44-wh5g"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/LibreChat-AI/LibreChat",
              "type": "GIT",
              "events": [
                {
                  "introduced": "24e8a258cd8fa1ff42c02cf15408079f1dbe07b0"
                },
                {
                  "fixed": "efbc088642afb69540efae9518b66e07760b23b7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0.8.2-rc2"
                      },
                      {
                        "fixed": "0.8.2"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "cpe": "cpe:2.3:a:librechat:librechat:0.8.2:rc2:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.8.2-rc2"
                      },
                      {
                        "last_affected": "0.8.2-rc2"
                      }
                    ],
                    "source": "CPE_STRING"
                  },
                  {
                    "cpe": "cpe:2.3:a:librechat:librechat:0.8.2:rc3:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0.8.2-rc3"
                      },
                      {
                        "last_affected": "0.8.2-rc3"
                      }
                    ],
                    "source": "CPE_STRING"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.8.2-rc2",
            "0.8.2-rc3",
            "v0.8.2-rc3",
            "chart-1.9.6",
            "v0.8.2-rc2",
            "chart-1.9.5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31950.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.483336941Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31950.json",
        "https://github.com/danny-avila/LibreChat/security/advisories/GHSA-f6rf-vm44-wh5g",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31950"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-284"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31950.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31950",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 513267,
  "published_at": "2026-03-27T19:25:25.007+00:00"
}