{"id":"CVE-2021-25944","aliases":["EUVD-2022-4090","GHSA-h6xg-rg33-9mf4"],"status":"published","title":"deep-defaults vulnerable to prototype pollution","description":"Prototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.","severity":{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-09","score":0.02961,"percentile":0.87308,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-1321"],"published":"2021-05-25T18:26:38Z","modified":"2026-06-17T03:42:39Z","affected":[{"source":"ghsa","ecosystem":"npm","package":"deep-defaults","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"1.0.0"},{"last_affected":"1.0.5"}]}]},{"source":"osv","ecosystem":"npm","package":"deep-defaults","ranges":[{"type":"SEMVER","events":[{"introduced":"1.0.0"},{"last_affected":"1.0.5"}]}]}],"products":[{"vendor":"deep-defaults_project","product":"deep-defaults"}],"references":[{"url":"https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25944","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-25944","tags":["advisory"]},{"url":"https://github.com/d5/deep-defaults/blob/321d0e2231aa807d54e7f95d75c22048a806923f/lib/index.js#L16","tags":["web"]},{"url":"https://web.archive.org/web/20210525211925/https://www.whitesourcesoftware.com/vulnerability-database/CVE-2021-25944","tags":["web"]},{"url":"https://github.com/advisories/GHSA-h6xg-rg33-9mf4"},{"url":"https://github.com/d5/deep-defaults","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2021-25944","description":"Prototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.","status":"published","published":"2021-05-25T18:26:38Z","modified":"2024-08-03T20:19:18.518Z","updated_at":"2026-11-02T14:32:59.430294Z"}],"euvd":[{"id":"EUVD-2022-4090","description":"Prototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.","status":"published","published":"2021-05-25T18:26:38Z","modified":"2024-08-03T20:19:18Z","updated_at":"2026-11-03T03:24:51.962182Z"}],"ghsa":[{"id":"GHSA-h6xg-rg33-9mf4","title":"deep-defaults vulnerable to prototype pollution","description":"### Overview\nPrototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.\n\n### Details\nThe NPM module `deep-defaults` can be abused by Prototype Pollution vulnerability since the function `_deepDefaults()` does not check for the type of object before assigning value to the property. Due to this flaw an attacker could create a non-existent property or able to manipulate the property which leads to Denial of Service or potentially Remote code execution.\n\n### PoC\nThe `_deepDefaults ()` function accepts `dest`, `src` as arguments. Due to the absence of validation on the values passed into the `src` argument, an attacker can supply a malicious value by adjusting the value to include the `__proto__` property. Since there is no validation before assigning the property to check whether the assigned argument is the Object's own property or not, the property `polluted` will be directly be assigned to the new object thereby polluting the Object prototype. Later in the code, if there is a check to validate `polluted` the valued would be substituted as \"Yes! Its Polluted\" as it had been polluted.\n\n```js\nvar deepDefaults = require(\"deep-defaults\")\nvar malicious_payload = '{\"__proto__\":{\"polluted\":\"Yes! Its Polluted\"}}';\nvar obj ={};\nconsole.log(\"Before : \" + {}.polluted);\ndeepDefaults(obj, JSON.parse(malicious_payload));\nconsole.log(\"After : \" + {}.polluted);\n```","status":"published","published":"2022-05-24T19:03:10Z","modified":"2024-04-22T23:22:36Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:37:44.335614Z"}],"nvd":[{"id":"CVE-2021-25944","description":"Prototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.","status":"published","published":"2021-05-25T19:15:07.683Z","modified":"2026-06-17T03:42:39.233Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":7.5,"vector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","level":"high","assessor":"primary"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T14:06:53.987491Z"}],"osv":[{"id":"GHSA-h6xg-rg33-9mf4","title":"deep-defaults vulnerable to prototype pollution","description":"### Overview\nPrototype pollution vulnerability in 'deep-defaults' versions 1.0.0 through 1.0.5 allows attacker to cause a denial of service and may lead to remote code execution.\n\n### Details\nThe NPM module `deep-defaults` can be abused by Prototype Pollution vulnerability since the function `_deepDefaults()` does not check for the type of object before assigning value to the property. Due to this flaw an attacker could create a non-existent property or able to manipulate the property which leads to Denial of Service or potentially Remote code execution.\n\n### PoC\nThe `_deepDefaults ()` function accepts `dest`, `src` as arguments. Due to the absence of validation on the values passed into the `src` argument, an attacker can supply a malicious value by adjusting the value to include the `__proto__` property. Since there is no validation before assigning the property to check whether the assigned argument is the Object's own property or not, the property `polluted` will be directly be assigned to the new object thereby polluting the Object prototype. Later in the code, if there is a check to validate `polluted` the valued would be substituted as \"Yes! Its Polluted\" as it had been polluted.\n\n```js\nvar deepDefaults = require(\"deep-defaults\")\nvar malicious_payload = '{\"__proto__\":{\"polluted\":\"Yes! Its Polluted\"}}';\nvar obj ={};\nconsole.log(\"Before : \" + {}.polluted);\ndeepDefaults(obj, JSON.parse(malicious_payload));\nconsole.log(\"After : \" + {}.polluted);\n```","status":"published","published":"2022-05-24T19:03:10Z","modified":"2024-04-22T23:44:02.619075Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-1321"],"updated_at":"2026-11-02T15:46:48.920784Z"}]}}