Dottie vulnerable to prototype pollution bypass via non-first path segments in set() and transform()

{
  "id": "62d5abd1a57d24e771c01271a1da10c90a19e172e9213411f0417c65a23d78e5",
  "url": "https://osv.dev/vulnerability/CVE-2026-27837",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Dottie vulnerable to prototype pollution bypass via non-first path segments in set() and transform()",
    "summary": "Dottie provides nested object access and manipulation in JavaScript. Versions 2.0.4 through 2.0.6 contain an incomplete fix for CVE-2023-26132. The prototype pollution guard introduced in commit `7d3aee1` only validates the first segment of a dot-separated path, allowing an attacker to bypass the protection by placing `__proto__` at any position other than the first. Both `dottie.set()` and `dottie.transform()` are affected. Version 2.0.7 contains an updated fix to address the residual vulnerability.",
    "evidence": "osv:CVE-2026-27837",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-27837",
      "aliases": [
        "CVE-2026-27837",
        "GHSA-r5mx-6wc6-7h9w"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/mickhansen/dottie.js",
              "type": "GIT",
              "events": [
                {
                  "introduced": "e0c8baee4e1551b6ce63cc0b5eef18e8362482c2"
                },
                {
                  "fixed": "334c32b80ed536522b567ee6a844caf8e5fef9c3"
                },
                {
                  "fixed": "7e8fa1345a4b46325f0eab8d7aeb1c4deaefdb14"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:dottie_project:dottie:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "2.0.4"
                      },
                      {
                        "fixed": "2.0.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "7e8fa1345a4b46325f0eab8d7aeb1c4deaefdb14"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v2.0.6",
            "v2.0.4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-27837.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.643527631Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27837.json",
        "https://github.com/advisories/GHSA-4gxf-g5gf-22h4",
        "https://github.com/mickhansen/dottie.js/security/advisories/GHSA-r5mx-6wc6-7h9w",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-27837",
        "https://github.com/mickhansen/dottie.js/commit/7e8fa1345a4b46325f0eab8d7aeb1c4deaefdb14"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27837.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-27837",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 521132,
  "published_at": "2026-02-26T00:19:24.289+00:00"
}