lodash vulnerable to Prototype Pollution via array path bypass in `_.unset` and `_.omit`

{
  "id": "5feb8ce6aea12bc5a14dc95b83606e8093c6d24fd099a8fd74407ee87a3c7592",
  "url": "https://osv.dev/vulnerability/GHSA-f23m-r3pf-42rh",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "lodash vulnerable to Prototype Pollution via array path bypass in `_.unset` and `_.omit`",
    "summary": "### Impact Lodash versions 4.17.23 and earlier are vulnerable to prototype pollution in the `_.unset` and `_.omit` functions. The fix for [CVE-2025-13465](https://github.com/lodash/lodash/security/advisories/GHSA-xxjr-mmjv-4gpg) only guards against string key members, so an attacker can bypass the check by passing array-wrapped path segments. This allows deletion of properties from built-in prototypes such as `Object.prototype`, `Number.prototype`, and `String.prototype`. The issue permits deletion of prototype properties but does not allow overwriting their original behavior. ### Patches This issue is patched in 4.18.0. ### Workarounds None. Upgrade to the patched version.",
    "evidence": "osv:GHSA-f23m-r3pf-42rh",
    "products": [
      {
        "name": {
          "value": "lodash",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.18.0",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "lodash-es",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.18.0",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "lodash-amd",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.18.0",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": []
      },
      {
        "name": {
          "value": "lodash.unset",
          "evidence": "/affected/3/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.18.0",
            "evidence": "/affected/3/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "GHSA-f23m-r3pf-42rh",
      "aliases": [
        "CVE-2026-2950",
        "GHSA-f23m-r3pf-42rh"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.18.0"
                }
              ]
            }
          ],
          "package": {
            "name": "lodash",
            "purl": "pkg:npm/lodash",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-f23m-r3pf-42rh/GHSA-f23m-r3pf-42rh.json",
            "last_known_affected_version_range": "<= 4.17.23"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.18.0"
                }
              ]
            }
          ],
          "package": {
            "name": "lodash-es",
            "purl": "pkg:npm/lodash-es",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-f23m-r3pf-42rh/GHSA-f23m-r3pf-42rh.json",
            "last_known_affected_version_range": "<= 4.17.23"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.18.0"
                }
              ]
            }
          ],
          "package": {
            "name": "lodash-amd",
            "purl": "pkg:npm/lodash-amd",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-f23m-r3pf-42rh/GHSA-f23m-r3pf-42rh.json",
            "last_known_affected_version_range": "<= 4.17.23"
          }
        },
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "4.0.0"
                },
                {
                  "fixed": "4.18.0"
                }
              ]
            }
          ],
          "package": {
            "name": "lodash.unset",
            "purl": "pkg:npm/lodash.unset",
            "ecosystem": "npm"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-f23m-r3pf-42rh/GHSA-f23m-r3pf-42rh.json"
          }
        }
      ],
      "modified": "2026-10-17T02:56:13.084362346Z",
      "provider": "osv",
      "references": [
        "https://github.com/lodash/lodash/security/advisories/GHSA-f23m-r3pf-42rh",
        "https://github.com/lodash/lodash/security/advisories/GHSA-xxjr-mmjv-4gpg",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-2950",
        "https://github.com/lodash/lodash"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-1321"
        ],
        "severity": "MODERATE",
        "github_reviewed": true,
        "nvd_published_at": "2026-03-31T20:16:26Z",
        "github_reviewed_at": "2026-04-01T23:50:27Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-2950",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 350174,
  "published_at": "2026-04-01T23:50:27+00:00"
}