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GHSA-HF2R-9GF9-RWCH

Vulnerability from github – Published: 2026-03-26 18:50 – Updated: 2026-03-26 18:50

Summary

Convict has prototype pollution via load(), loadFile(), and schema initialization

Details

Impact

Two unguarded prototype pollution paths exist, not covered by previous fixes:

config.load() / config.loadFile() — overlay() recursively merges config data without checking for forbidden keys. Input containing__proto__ or constructor.prototype (e.g. from a JSON file) causes the recursion to reach Object.prototype and write attacker-controlled values onto it.
Schema initialization — passing a schema with constructor.prototype.* keys to convict({...}) causes default-value propagation to write directly to Object.prototype at startup.

Depending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.

Workarounds

Do not pass untrusted data to load(), loadFile(), or convict().

Resources

Prior advisory: GHSA-44fc-8fm5-q62h Related issue: https://github.com/mozilla/node-convict/issues/423

Severity

9.4 (Critical)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 6.2.4"
      },
      "package": {
        "ecosystem": "npm",
        "name": "convict"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.2.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-33863"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-26T18:50:33Z",
    "nvd_published_at": null,
    "severity": "CRITICAL"
  },
  "details": "### Impact\nTwo unguarded prototype pollution paths exist, not covered by previous fixes:\n\n1. `config.load()` / `config.loadFile()` \u2014 `overlay()` recursively merges config data without checking for forbidden keys. Input containing` __proto__` or `constructor.prototype` (e.g. from a JSON file) causes the recursion to reach `Object.prototype` and write attacker-controlled values onto it.\n2. Schema initialization \u2014 passing a schema with `constructor.prototype.*` keys to `convict({...})` causes default-value propagation to write directly to `Object.prototype` at startup.\n\nDepending on how polluted properties are consumed, impact ranges from unexpected behavior to authentication bypass or RCE.\n\n### Workarounds\nDo not pass untrusted data to load(), loadFile(), or convict().\n\n### Resources\nPrior advisory: [GHSA-44fc-8fm5-q62h](https://github.com/mozilla/node-convict/security/advisories/GHSA-44fc-8fm5-q62h)\nRelated issue: [https://github.com/mozilla/node-convict/issues/423](https://github.com/mozilla/node-convict/issues/423)",
  "id": "GHSA-hf2r-9gf9-rwch",
  "modified": "2026-03-26T18:50:34Z",
  "published": "2026-03-26T18:50:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mozilla/node-convict/security/advisories/GHSA-44fc-8fm5-q62h"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mozilla/node-convict/security/advisories/GHSA-hf2r-9gf9-rwch"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mozilla/node-convict/issues/423"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mozilla/node-convict"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Convict has prototype pollution via load(), loadFile(), and schema initialization"
}

Sightings

Author	Source	Type	Date	Other

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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