@phun-ky/defaults-deep Has a Prototype Pollution issue via Unsafe Recursive Property Merging

{
  "id": "2f1a97f21ef16c00de8c635f3113177ecca804f2cb6e222492436fcd1e48cc23",
  "url": "https://osv.dev/vulnerability/CVE-2026-54737",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "@phun-ky/defaults-deep Has a Prototype Pollution issue via Unsafe Recursive Property Merging",
    "summary": "@phun-ky/defaults-deep is a library like lodash defaultsDeep with array preservation and no lodash dependency. Prior to 2.0.5, defaultsDeep() recursively merges user-supplied objects without filtering proto, constructor, and prototype, allowing properties to be written to Object.prototype. This issue is fixed in version 2.0.5.",
    "evidence": "osv:CVE-2026-54737",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-54737",
      "aliases": [
        "CVE-2026-54737",
        "GHSA-mj3g-7xcc-x4vh"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/phun-ky/defaults-deep",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "f585c805d4a6763adef0cd05cc5e5d80b89a0dd6"
                },
                {
                  "fixed": "807dba930f8718f9126cad59d949b8fd3539b059"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "2.0.5"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "807dba930f8718f9126cad59d949b8fd3539b059"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "f585c805d4a6763adef0cd05cc5e5d80b89a0dd6"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "2.0.5"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.0.4",
            "2.0.3",
            "2.0.2",
            "2.0.1",
            "2.0.0",
            "1.1.19",
            "1.1.18",
            "1.1.17",
            "1.1.16",
            "1.1.15",
            "1.1.14",
            "1.1.13",
            "1.1.12",
            "1.1.11",
            "1.1.10",
            "1.1.9",
            "1.1.8",
            "1.1.7",
            "1.1.6",
            "1.1.5",
            "1.1.4",
            "1.1.3",
            "1.1.2",
            "1.1.1",
            "1.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-54737.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:45.968873204Z",
      "provider": "osv",
      "references": [
        "https://github.com/phun-ky/defaults-deep/releases/tag/2.0.5",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54737.json",
        "https://github.com/phun-ky/defaults-deep/security/advisories/GHSA-mj3g-7xcc-x4vh",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-54737",
        "https://github.com/phun-ky/defaults-deep/commit/807dba930f8718f9126cad59d949b8fd3539b059",
        "https://github.com/phun-ky/defaults-deep/pull/49"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/54xxx/CVE-2026-54737.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-54737",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 514280,
  "published_at": "2026-07-31T17:48:42.67+00:00"
}