Let's Chat 0.4.0 - 0.4.8 Denial of Service via Null Dereference in Room Lookup

{
  "id": "b01cc7ec751b4f41d3eba1604f80df587d681b9d3fb0ba041851facbf192efd5",
  "url": "https://osv.dev/vulnerability/CVE-2026-66749",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Let's Chat 0.4.0 - 0.4.8 Denial of Service via Null Dereference in Room Lookup",
    "summary": "Let's Chat 0.4.0 through 0.4.8 contains a null dereference vulnerability that allows authenticated attackers to crash the server by supplying a valid 24-character hex string room parameter that matches no document in the database. Attackers can send a crafted GET /messages request causing an uncaught TypeError in an asynchronous Mongoose callback that terminates the Node.js server process, with the same defect reachable through multiple code paths including the socket.io interface.",
    "evidence": "osv:CVE-2026-66749",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-66749",
      "aliases": [
        "CVE-2026-66749"
      ],
      "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/sdelements/lets-chat",
              "type": "GIT",
              "events": [
                {
                  "introduced": "84981a6d2534445c00ea4e095c934e46943c0b1d"
                },
                {
                  "last_affected": "617207ff3c0c0bf8e3c7a915bd9ec03f1dd8390c"
                },
                {
                  "introduced": "ebdd712cec56da494e04f3505d10026e6f25051a"
                },
                {
                  "last_affected": "a5e8b2d5977fedc167e1efb03a4f80121da4842e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "84981a6d2534445c00ea4e095c934e46943c0b1d"
                      },
                      {
                        "last_affected": "617207ff3c0c0bf8e3c7a915bd9ec03f1dd8390c"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0.4.0"
                      },
                      {
                        "last_affected": "0.4.8"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.4.8",
            "0.4.7",
            "0.4.6",
            "0.4.5",
            "0.4.4",
            "0.4.3",
            "0.4.2",
            "0.4.1",
            "0.4.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-66749.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:40.170588633Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66749.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-66749",
        "https://www.vulncheck.com/advisories/let-s-chat-denial-of-service-via-null-dereference-in-room-lookup",
        "https://github.com/sdelements/lets-chat",
        "https://github.com/theopaid/Unchecked-Room-Lookup-Leads-to-Server-Crash-Let-s-Chat-"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-476"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/66xxx/CVE-2026-66749.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-66749",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 507787,
  "published_at": "2026-07-28T15:30:46.773+00:00"
}