multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception

{
  "id": "7d7e21a0d391b1ac894223158f0fe13be71808e4e4812968b72065a36401098c",
  "url": "https://osv.dev/vulnerability/CVE-2026-8161",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception",
    "summary": "multiparty@4.2.3 and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/form-data request with a field name that collides with an inherited Object.prototype property such as __proto__, constructor, or toString, the parser invokes .push() on the inherited prototype value rather than an array, throwing a TypeError that propagates as an uncaught exception and crashes the process. Impact: any service accepting multipart uploads via multiparty is affected. Workarounds: none. Upgrade to multiparty@4.3.0 or higher.",
    "evidence": "osv:CVE-2026-8161",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-8161",
      "aliases": [
        "CVE-2026-8161",
        "GHSA-qxch-whhj-8956"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/pillarjs/multiparty",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "f7963dbfb8c66764790790cf79eb0992c0e45ff0"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "last_affected": "4.2.3"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "cpe": "cpe:2.3:a:pillarjs:multiparty:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.3.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "4.2.3",
            "4.2.2",
            "4.2.1",
            "4.2.0",
            "4.1.4",
            "4.1.3",
            "4.1.2",
            "4.1.1",
            "4.1.0",
            "4.0.0",
            "3.3.2",
            "3.3.1",
            "3.3.0",
            "3.2.9",
            "3.2.8",
            "3.2.7",
            "3.2.6",
            "3.2.5",
            "3.2.4",
            "3.2.2",
            "3.2.3",
            "3.2.1",
            "3.2.0",
            "3.1.2",
            "3.1.1",
            "3.1.0",
            "3.0.0",
            "2.2.0",
            "2.1.9",
            "2.1.8",
            "2.1.7",
            "2.1.6",
            "2.1.5",
            "2.1.4",
            "2.1.3",
            "2.1.2",
            "2.1.1",
            "2.1.0",
            "2.0.0",
            "v1.0.11",
            "v1.0.10",
            "v1.0.9",
            "v1.0.8",
            "v1.0.7",
            "v1.0.6",
            "v1.0.5",
            "v1.0.4",
            "v1.0.3",
            "v1.0.2",
            "v1.0.1",
            "v1.0.0",
            "v0.9.11",
            "v0.9.10",
            "v0.9.9",
            "v0.9.8",
            "v0.9.7",
            "v0.9.6",
            "v0.9.5",
            "v0.9.4",
            "v0.9.3",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0",
            "v0.8.0",
            "v0.7.0",
            "v0.6.0",
            "v0.5.0",
            "v0.4.0",
            "v0.3.0",
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-8161.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.455134991Z",
      "provider": "osv",
      "references": [
        "https://cna.openjsf.org/security-advisories.html",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8161.json",
        "https://github.com/pillarjs/multiparty/security/advisories/GHSA-qxch-whhj-8956",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-8161"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321",
          "CWE-248"
        ],
        "cna_assigner": "openjs",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8161.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-8161",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493889,
  "published_at": "2026-05-12T08:50:37.685+00:00"
}