CVE-2026-4800: Lodash Lodash Vulnerable To Code Injection Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-r5fr-rjxr-66jc",
  "modified" : "2026-04-01T23:51:12Z",
  "published" : "2026-04-01T23:51:12Z",
  "aliases" : [ "CVE-2026-4800" ],
  "summary" : "lodash vulnerable to Code Injection via `_.template` imports key names",
  "details" : "### Impact\n\nThe fix for [CVE-2021-23337](https://github.com/advisories/GHSA-35jh-r3h4-6jhm) added validation for the `variable` option in `_.template` but did not apply the same validation to `options.imports` key names. Both paths flow into the same `Function()` constructor sink.\n\nWhen an application passes untrusted input as `options.imports` key names, an attacker can inject default-parameter expressions that execute arbitrary code at template compilation time.\n\nAdditionally, `_.template` uses `assignInWith` to merge imports, which enumerates inherited properties via `for..in`. If `Object.prototype` has been polluted by any other vector, the polluted keys are copied into the imports object and passed to `Function()`.\n\n### Patches\n\nUsers should upgrade to version 4.18.0.\n\nThe fix applies two changes:\n1. Validate `importsKeys` against the existing `reForbiddenIdentifierChars` regex (same check already used for the `variable` option)\n2. Replace `assignInWith` with `assignWith` when merging imports, so only own properties are enumerated\n\n### Workarounds\n\nDo not pass untrusted input as key names in `options.imports`. Only use developer-controlled, static key names.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "lodash"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.17.23"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "lodash-es"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.17.23"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "lodash-amd"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.18.0"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 4.17.23"
    }
  }, {
    "package" : {
      "ecosystem" : "npm",
      "name" : "lodash.template"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "4.0.0"
      }, {
        "fixed" : "4.18.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/lodash/lodash/security/advisories/GHSA-r5fr-rjxr-66jc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-4800"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/lodash/lodash/commit/3469357cff396a26c363f8c1b5a91dde28ba4b1c"
  }, {
    "type" : "WEB",
    "url" : "https://cna.openjsf.org/security-advisories.html"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-35jh-r3h4-6jhm"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/lodash/lodash"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-04-01T23:51:12Z",
    "nvd_published_at" : "2026-03-31T20:16:29Z"
  }
}