sveltekit-superforms Prototype Pollution in `parseFormData` function of `formData.js`

{
  "id": "5c1a161f454ddbbcd7a0f1114c83575e556a4fabf27be1b649b599cdd1655385",
  "url": "https://osv.dev/vulnerability/CVE-2025-62381",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sveltekit-superforms Prototype Pollution in `parseFormData` function of `formData.js`",
    "summary": "sveltekit-superforms makes SvelteKit forms a pleasure to use. sveltekit-superforms v2.27.3 and prior are susceptible to a prototype pollution vulnerability within the parseFormData function of formData.js. An attacker can inject string and array properties into Object.prototype, leading to denial of service, type confusion, and potential remote code execution in downstream applications that rely on polluted objects. This vulnerability is fixed in 2.27.4.",
    "evidence": "osv:CVE-2025-62381",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-62381",
      "aliases": [
        "CVE-2025-62381",
        "GHSA-hwmc-4c8j-xxj7"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ciscoheat/sveltekit-superforms",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "34f1abf0c8992213c9bcc571c1f13e09b539db71"
                },
                {
                  "fixed": "4a1310dd1a94176bb22036662c530dad48059ca4"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.27.4"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "4a1310dd1a94176bb22036662c530dad48059ca4"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.27.3",
            "v2.27.2",
            "v2.27.1",
            "v2.27.0",
            "v2.26.1",
            "v2.26.0",
            "v2.25.0",
            "v2.24.1",
            "v2.24.0",
            "v2.23.0",
            "v2.22.1",
            "v2.22.0",
            "v2.21.1",
            "v2.21.0",
            "v2.20.1",
            "v2.19.1",
            "v2.19.0",
            "v2.18.1",
            "v2.18.0",
            "v2.17.0",
            "v2.16.1",
            "v2.16.0",
            "v2.15.2",
            "v2.15.1",
            "v2.15.0",
            "v2.14.0",
            "v2.13.1",
            "v2.13.0",
            "v2.12.6",
            "v2.12.3",
            "v2.12.0",
            "v2.11.0",
            "v2.10.6",
            "v2.10.5",
            "v2.9.0",
            "v2.8.0",
            "v2.7.0",
            "v2.6.1",
            "v2.6.0",
            "v2.5.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-62381.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.784886923Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/62xxx/CVE-2025-62381.json",
        "https://github.com/ciscoheat/sveltekit-superforms/security/advisories/GHSA-hwmc-4c8j-xxj7",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-62381",
        "https://github.com/ciscoheat/sveltekit-superforms/commit/4a1310dd1a94176bb22036662c530dad48059ca4"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/62xxx/CVE-2025-62381.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-62381",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505199,
  "published_at": "2025-10-15T17:12:47.357+00:00"
}