Common Weakness Enumeration

CWE-1321

Allowed

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

Abstraction: Variant · Status: Incomplete

The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

940 vulnerabilities reference this CWE, most recent first.

GHSA-VQQW-FR4W-V889

Vulnerability from github – Published: 2024-12-18 12:30 – Updated: 2026-04-01 18:32
VLAI
Details

Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability in Mighty Digital Partners allows Object Injection.This issue affects Partners: from n/a through 0.2.0.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2024-56059"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-12-18T12:15:12Z",
    "severity": "CRITICAL"
  },
  "details": "Improperly Controlled Modification of Object Prototype Attributes (\u0027Prototype Pollution\u0027) vulnerability in Mighty Digital Partners allows Object Injection.This issue affects Partners: from n/a through 0.2.0.",
  "id": "GHSA-vqqw-fr4w-v889",
  "modified": "2026-04-01T18:32:52Z",
  "published": "2024-12-18T12:30:55Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-56059"
    },
    {
      "type": "WEB",
      "url": "https://patchstack.com/database/wordpress/plugin/partners/vulnerability/wordpress-partners-plugin-0-2-0-php-object-injection-vulnerability?_s_id=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VR5M-3H59-7JCP

Vulnerability from github – Published: 2021-07-01 17:01 – Updated: 2022-05-26 19:57
VLAI
Summary
Prototype Pollution in think-helper
Details

Impact

The software receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

Patches

think-helper@1.1.3 patched it, anyone used think-helper should upgrade to >=1.1.3 version.

References

https://cwe.mitre.org/data/definitions/1321.html

For more information

If you have any questions or comments about this advisory: * Open an issue in thinkjs/thinkjs * Email us at i@imnerd.org

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "think-helper"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-32736"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321",
      "CWE-915"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-06-30T17:40:38Z",
    "nvd_published_at": "2021-06-30T18:15:00Z",
    "severity": "HIGH"
  },
  "details": "### Impact\n\nThe software receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.\n\n### Patches\n\n`think-helper@1.1.3` patched it, anyone used `think-helper` should upgrade to `\u003e=1.1.3` version.\n\n### References\n\nhttps://cwe.mitre.org/data/definitions/1321.html\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [thinkjs/thinkjs](https://github.com/thinkjs/thinkjs)\n* Email us at [i@imnerd.org](mailto:i@imnerd.org)\n",
  "id": "GHSA-vr5m-3h59-7jcp",
  "modified": "2022-05-26T19:57:25Z",
  "published": "2021-07-01T17:01:59Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/thinkjs/think-helper/security/advisories/GHSA-vr5m-3h59-7jcp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-32736"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/thinkjs/think-helper"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Prototype Pollution in think-helper"
}

GHSA-VRFH-PH2R-GXR9

Vulnerability from github – Published: 2025-02-06 06:31 – Updated: 2025-02-06 15:32
VLAI
Details

A prototype pollution in the lib.post function of ajax-request v1.2.3 allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2024-57076"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321",
      "CWE-400"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2025-02-05T22:15:31Z",
    "severity": "HIGH"
  },
  "details": "A prototype pollution in the lib.post function of ajax-request v1.2.3 allows attackers to cause a Denial of Service (DoS) via supplying a crafted payload.",
  "id": "GHSA-vrfh-ph2r-gxr9",
  "modified": "2025-02-06T15:32:52Z",
  "published": "2025-02-06T06:31:26Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-57076"
    },
    {
      "type": "WEB",
      "url": "https://gist.github.com/tariqhawis/c432b93ee7d967c2e65bc1bf39241664"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VRR3-5R3V-7XFW

Vulnerability from github – Published: 2021-05-17 21:00 – Updated: 2023-09-13 19:52
VLAI
Summary
Improperly Controlled Modification of Dynamically-Determined Object Attributes in casperjs
Details

Overview

casperjs is a navigation scripting & testing utility for PhantomJS and SlimerJS.

Affected versions of this package are vulnerable to Prototype Pollution via the mergeObjects utility function.

PoC

var payload = JSON.parse('{"__proto__": {"a": "pwned"}}');
mergeObjects({}, payload);
console.log({}.a); // prints "pwned"
Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "casperjs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "1.1.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2020-7679"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321",
      "CWE-915"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-05-11T22:26:54Z",
    "nvd_published_at": "2020-06-19T11:15:00Z",
    "severity": "HIGH"
  },
  "details": "### Overview\ncasperjs is a navigation scripting \u0026 testing utility for PhantomJS and SlimerJS.\n\nAffected versions of this package are vulnerable to Prototype Pollution via the mergeObjects utility function.\n\n### PoC\n```js\nvar payload = JSON.parse(\u0027{\"__proto__\": {\"a\": \"pwned\"}}\u0027);\nmergeObjects({}, payload);\nconsole.log({}.a); // prints \"pwned\"\n```",
  "id": "GHSA-vrr3-5r3v-7xfw",
  "modified": "2023-09-13T19:52:14Z",
  "published": "2021-05-17T21:00:52Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-7679"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/casperjs/casperjs"
    },
    {
      "type": "WEB",
      "url": "https://github.com/casperjs/casperjs/blob/master/modules/utils.js%23L680"
    },
    {
      "type": "WEB",
      "url": "https://snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-572804"
    },
    {
      "type": "WEB",
      "url": "https://snyk.io/vuln/SNYK-JS-CASPERJS-572803"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Improperly Controlled Modification of Dynamically-Determined Object Attributes in casperjs"
}

GHSA-VRW9-G62V-7FMF

Vulnerability from github – Published: 2025-09-24 18:30 – Updated: 2026-01-27 21:06
VLAI
Summary
CSVTOJSON has a prototype pollution vulnerability
Details

The csvtojson package, a tool for converting CSV data to JSON with customizable parsing capabilities, contains a prototype pollution vulnerability in versions prior to 2.0.10. This issue arises due to insufficient sanitization of nested header names during the parsing process in the parser_jsonarray component. When processing CSV input containing specially crafted header fields that reference prototype chains (e.g., using proto syntax), the application may unintentionally modify properties of the base Object prototype. This vulnerability can lead to denial of service conditions or unexpected behavior in applications relying on unmodified prototype chains, particularly when untrusted CSV data is processed. The flaw does not require user interaction beyond providing a maliciously constructed CSV file.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "csvtojson"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "2.0.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-57350"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2025-09-24T20:10:59Z",
    "nvd_published_at": "2025-09-24T18:15:41Z",
    "severity": "MODERATE"
  },
  "details": "The csvtojson package, a tool for converting CSV data to JSON with customizable parsing capabilities, contains a prototype pollution vulnerability in versions prior to 2.0.10. This issue arises due to insufficient sanitization of nested header names during the parsing process in the parser_jsonarray component. When processing CSV input containing specially crafted header fields that reference prototype chains (e.g., using __proto__ syntax), the application may unintentionally modify properties of the base Object prototype. This vulnerability can lead to denial of service conditions or unexpected behavior in applications relying on unmodified prototype chains, particularly when untrusted CSV data is processed. The flaw does not require user interaction beyond providing a maliciously constructed CSV file.",
  "id": "GHSA-vrw9-g62v-7fmf",
  "modified": "2026-01-27T21:06:02Z",
  "published": "2025-09-24T18:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-57350"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Keyang/node-csvtojson/issues/498"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Keyang/node-csvtojson/issues/502"
    },
    {
      "type": "WEB",
      "url": "https://github.com/Keyang/node-csvtojson/commit/4caeebd13b67be63282a7bbed3ca0cf9813f4bfc"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/Keyang/node-csvtojson"
    },
    {
      "type": "WEB",
      "url": "https://github.com/VulnSageAgent/PoCs/tree/main/JavaScript/prototype-pollution/CVE-2025-57350"
    },
    {
      "type": "WEB",
      "url": "https://security.snyk.io/vuln/SNYK-JS-CSVTOJSON-13109616"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "CSVTOJSON has a prototype pollution vulnerability"
}

GHSA-VVV8-XW5F-3F88

Vulnerability from github – Published: 2022-06-18 00:00 – Updated: 2022-06-20 22:33
VLAI
Summary
Prototype Pollution in mout
Details

This affects all versions of package mout. The deepFillIn function can be used to 'fill missing properties recursively', while the deepMixIn mixes objects into the target object, recursively mixing existing child objects as well. In both cases, the key used to access the target object recursively is not checked, leading to exploiting this vulnerability. Note: This vulnerability derives from an incomplete fix of CVE-2020-7792.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.2.3"
      },
      "package": {
        "ecosystem": "npm",
        "name": "mout"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-21213"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-06-20T22:33:58Z",
    "nvd_published_at": "2022-06-17T20:15:00Z",
    "severity": "HIGH"
  },
  "details": "This affects all versions of package mout. The deepFillIn function can be used to \u0027fill missing properties recursively\u0027, while the deepMixIn mixes objects into the target object, recursively mixing existing child objects as well. In both cases, the key used to access the target object recursively is not checked, leading to exploiting this vulnerability. **Note:** This vulnerability derives from an incomplete fix of [CVE-2020-7792](https://security.snyk.io/vuln/SNYK-JS-MOUT-1014544).",
  "id": "GHSA-vvv8-xw5f-3f88",
  "modified": "2022-06-20T22:33:58Z",
  "published": "2022-06-18T00:00:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-21213"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mout/mout/pull/279"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mout/mout/commit/17ffdc2a96417a63a0147156dc045e90d0d14c64"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mout/mout"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mout/mout/blob/master/src/object/deepFillIn.js"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mout/mout/blob/master/src/object/deepMixIn.js"
    },
    {
      "type": "WEB",
      "url": "https://snyk.io/vuln/SNYK-JS-MOUT-2342654"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Prototype Pollution in mout"
}

GHSA-VWHQ-PM3R-FJM9

Vulnerability from github – Published: 2022-09-16 00:00 – Updated: 2022-09-21 21:08
VLAI
Summary
steal vulnerable to Prototype Pollution via key variable in babel.js
Details

Prototype pollution vulnerability in function extend in babel.js in stealjs steal via the key variable in babel.js.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "steal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "2.3.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2022-37266"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2022-09-21T21:08:01Z",
    "nvd_published_at": "2022-09-15T13:15:00Z",
    "severity": "CRITICAL"
  },
  "details": "Prototype pollution vulnerability in function extend in babel.js in stealjs steal via the key variable in babel.js.",
  "id": "GHSA-vwhq-pm3r-fjm9",
  "modified": "2022-09-21T21:08:01Z",
  "published": "2022-09-16T00:00:39Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2022-37266"
    },
    {
      "type": "WEB",
      "url": "https://github.com/stealjs/steal/issues/1535"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/stealjs/steal"
    },
    {
      "type": "WEB",
      "url": "https://github.com/stealjs/steal/blob/c9dd1eb19ed3f97aeb93cf9dcea5d68ad5d0ced9/ext/babel.js#L29165"
    },
    {
      "type": "WEB",
      "url": "https://github.com/stealjs/steal/blob/c9dd1eb19ed3f97aeb93cf9dcea5d68ad5d0ced9/ext/babel.js#L29169"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "steal vulnerable to Prototype Pollution via key variable in babel.js"
}

GHSA-VWQG-8V6M-FH9W

Vulnerability from github – Published: 2022-05-24 16:58 – Updated: 2022-12-02 21:30
VLAI
Details

SugarCRM before 8.0.4 and 9.x before 9.0.2 allows PHP object injection in the UpgradeWizard module by an Admin user.

Show details on source website

{
  "affected": [],
  "aliases": [
    "CVE-2019-17317"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2019-10-07T15:15:00Z",
    "severity": "MODERATE"
  },
  "details": "SugarCRM before 8.0.4 and 9.x before 9.0.2 allows PHP object injection in the UpgradeWizard module by an Admin user.",
  "id": "GHSA-vwqg-8v6m-fh9w",
  "modified": "2022-12-02T21:30:46Z",
  "published": "2022-05-24T16:58:09Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2019-17317"
    },
    {
      "type": "WEB",
      "url": "https://support.sugarcrm.com/Resources/Security/sugarcrm-sa-2019-044"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

GHSA-VWRP-X96C-MHWQ

Vulnerability from github – Published: 2026-05-07 04:07 – Updated: 2026-05-14 20:36
VLAI
Summary
vm2: Mutable Proxies for Host Intrinsic Prototypes Allows Sandbox Escape
Details

Summary

vm2's bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying host objects with otherReflectSet() and otherReflectDefineProperty(), which lets attacker-controlled JavaScript running in a default VM or inherited NodeVM mutate shared host Object.prototype, Array.prototype, and Function.prototype from inside the sandbox.

Details

BaseHandler.apply() unwraps sandbox-controlled receivers and arguments with otherFromThis() / otherFromThisArguments() and then directly invokes the real host function with ret = otherReflectApply(object, context, args), so any default-exposed host function that can surface a prototype getter becomes a prototype-walking primitive (lib/bridge.js:665-676). BaseHandler.get() special-cases proto and returns the host-side descriptor or proxy target prototype, which is enough for the attacker to reuse the host lookupGetter('proto') accessor repeatedly until the walk lands on host Object.prototype, Array.prototype, or Function.prototype (lib/bridge.js:590-616). Once the attacker has a proxy to a host intrinsic prototype, BaseHandler.set() performs value = otherFromThis(value); return otherReflectSet(object, key, value) === true;, which writes attacker-controlled data directly into the shared host object instead of keeping the mutation sandbox-local; BaseHandler.defineProperty() repeats the same design at otherReflectDefineProperty(object, prop, otherDesc) for descriptor-based writes (lib/bridge.js:641-649, lib/bridge.js:753-774). Existing validation does not stop the attack because the constructor filter only blocks one dangerous-property access pattern, setPrototypeOf() only blocks prototype replacement rather than ordinary property assignment, and containsDangerousConstructor() only protects one later re-unwrapping path instead of the initial host-prototype write sink (lib/bridge.js:494-530, lib/bridge.js:595-610, lib/bridge.js:660-662).

PoC

Run the following code snippet and observe that the value of vm2EscapeMarker is polluted:

const { VM } = require('vm2');
const vm = new VM();
vm.run(`
  const g = ({}).__lookupGetter__;
  const a = Buffer.apply;
  const p = a.apply(g, [Buffer, ['__proto__']]);
  const hostObjectProto = p.call(p.call(p.call(p.call(Buffer.of()))));
  hostObjectProto.vm2EscapeMarker = 'polluted-object-prototype';
`);
console.log({}.vm2EscapeMarker)

Impact

Sandbox escape and prototype pollution.

Show details on source website

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.10.5"
      },
      "package": {
        "ecosystem": "npm",
        "name": "vm2"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.9.6"
            },
            {
              "fixed": "3.11.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-44005"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321",
      "CWE-94"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-05-07T04:07:05Z",
    "nvd_published_at": "2026-05-13T18:16:17Z",
    "severity": "CRITICAL"
  },
  "details": "### Summary\nvm2\u0027s bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying host objects with otherReflectSet() and otherReflectDefineProperty(), which lets attacker-controlled JavaScript running in a default VM or inherited NodeVM mutate shared host Object.prototype, Array.prototype, and Function.prototype from inside the sandbox.\n\n### Details\nBaseHandler.apply() unwraps sandbox-controlled receivers and arguments with otherFromThis() / otherFromThisArguments() and then directly invokes the real host function with ret = otherReflectApply(object, context, args), so any default-exposed host function that can surface a prototype getter becomes a prototype-walking primitive ([lib/bridge.js:665-676](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L665-L676)). BaseHandler.get() special-cases __proto__ and returns the host-side descriptor or proxy target prototype, which is enough for the attacker to reuse the host __lookupGetter__(\u0027__proto__\u0027) accessor repeatedly until the walk lands on host Object.prototype, Array.prototype, or Function.prototype ([lib/bridge.js:590-616](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L590-L616)). Once the attacker has a proxy to a host intrinsic prototype, BaseHandler.set() performs value = otherFromThis(value); return otherReflectSet(object, key, value) === true;, which writes attacker-controlled data directly into the shared host object instead of keeping the mutation sandbox-local; BaseHandler.defineProperty() repeats the same design at otherReflectDefineProperty(object, prop, otherDesc) for descriptor-based writes ([lib/bridge.js:641-649](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L641-L649), [lib/bridge.js:753-774](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L753-L774)). Existing validation does not stop the attack because the constructor filter only blocks one dangerous-property access pattern, setPrototypeOf() only blocks prototype replacement rather than ordinary property assignment, and containsDangerousConstructor() only protects one later re-unwrapping path instead of the initial host-prototype write sink ([lib/bridge.js:494-530](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L494-L530), [lib/bridge.js:595-610](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L595-L610), [lib/bridge.js:660-662](https://github.com/patriksimek/vm2/blob/408fc855f1cc1bbc2985b029465ee0e732ada433/lib/bridge.js#L660-L662)).\n\n### PoC\nRun the following code snippet and observe that the value of vm2EscapeMarker is polluted:\n```\nconst { VM } = require(\u0027vm2\u0027);\nconst vm = new VM();\nvm.run(`\n  const g = ({}).__lookupGetter__;\n  const a = Buffer.apply;\n  const p = a.apply(g, [Buffer, [\u0027__proto__\u0027]]);\n  const hostObjectProto = p.call(p.call(p.call(p.call(Buffer.of()))));\n  hostObjectProto.vm2EscapeMarker = \u0027polluted-object-prototype\u0027;\n`);\nconsole.log({}.vm2EscapeMarker)\n```\n\n### Impact\nSandbox escape and prototype pollution.",
  "id": "GHSA-vwrp-x96c-mhwq",
  "modified": "2026-05-14T20:36:31Z",
  "published": "2026-05-07T04:07:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/patriksimek/vm2/security/advisories/GHSA-vwrp-x96c-mhwq"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44005"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/patriksimek/vm2"
    },
    {
      "type": "WEB",
      "url": "https://github.com/patriksimek/vm2/releases/tag/v3.11.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "vm2: Mutable Proxies for Host Intrinsic Prototypes Allows Sandbox Escape"
}

GHSA-VXR4-RXW7-G7V6

Vulnerability from github – Published: 2021-12-16 14:30 – Updated: 2023-09-11 16:21
VLAI
Summary
Prototype Pollution in comb
Details

All versions of package comb are vulnerable to Prototype Pollution via the deepMerge() function.

Show details on source website

{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "comb"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "2.0.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2021-23561"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2021-12-14T14:30:03Z",
    "nvd_published_at": "2021-12-10T20:15:00Z",
    "severity": "MODERATE"
  },
  "details": "All versions of package comb are vulnerable to Prototype Pollution via the `deepMerge()` function.",
  "id": "GHSA-vxr4-rxw7-g7v6",
  "modified": "2023-09-11T16:21:17Z",
  "published": "2021-12-16T14:30:56Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-23561"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/C2FO/comb"
    },
    {
      "type": "WEB",
      "url": "https://snyk.io/vuln/SNYK-JS-COMB-1730083"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Prototype Pollution in comb"
}

Mitigation
Implementation

By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.

Mitigation
Architecture and Design

By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.

Mitigation
Implementation

Strategy: Input Validation

When handling untrusted objects, validating using a schema can be used.

Mitigation
Implementation

By using an object without prototypes (via Object.create(null) ), adding object prototype attributes by accessing the prototype via the special attributes becomes impossible, mitigating this weakness.

Mitigation
Implementation

Map can be used instead of objects in most cases. If Map methods are used instead of object attributes, it is not possible to access the object prototype or modify it.

CAPEC-1: Accessing Functionality Not Properly Constrained by ACLs

In applications, particularly web applications, access to functionality is mitigated by an authorization framework. This framework maps Access Control Lists (ACLs) to elements of the application's functionality; particularly URL's for web apps. In the case that the administrator failed to specify an ACL for a particular element, an attacker may be able to access it with impunity. An attacker with the ability to access functionality not properly constrained by ACLs can obtain sensitive information and possibly compromise the entire application. Such an attacker can access resources that must be available only to users at a higher privilege level, can access management sections of the application, or can run queries for data that they otherwise not supposed to.

CAPEC-180: Exploiting Incorrectly Configured Access Control Security Levels

An attacker exploits a weakness in the configuration of access controls and is able to bypass the intended protection that these measures guard against and thereby obtain unauthorized access to the system or network. Sensitive functionality should always be protected with access controls. However configuring all but the most trivial access control systems can be very complicated and there are many opportunities for mistakes. If an attacker can learn of incorrectly configured access security settings, they may be able to exploit this in an attack.

CAPEC-77: Manipulating User-Controlled Variables

This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.