{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 5.0.44"
      },
      "package": {
        "ecosystem": "npm",
        "name": "@feathersjs/commons"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.0.45"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-54335"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1321"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-07-14T19:40:05Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Impact\n\nThe `_.merge(target, source)` utility exported by `@feathersjs/commons` recursively merges `source` into `target` by iterating `Object.keys(source)`. When `source` was produced by `JSON.parse` and contains a `__proto__` (or `constructor` / `prototype`) key, that key is returned as an own-enumerable property. The recursive merge then resolves `target[\u0027__proto__\u0027]` to `Object.prototype` and writes the attacker-supplied properties onto it, polluting the prototype for all plain objects in the process for the lifetime of the Node process.\n\n**Scope of real-world risk is limited.** No first-party Feathers package routes input \u2014 trusted or untrusted \u2014 through `commons._.merge`. The `@feathersjs/authentication` package, which does merge request-influenced data, uses `lodash/merge` (prototype-pollution-safe since 4.17.12), not this utility. Exploitation therefore requires a downstream plugin or application to pass JSON-parsed, attacker-controlled input directly through the exported `_.merge`.\n\n### Patches\n\nFixed in `@feathersjs/commons@5.0.45`. The fix skips `__proto__`, `constructor`, and `prototype` keys during iteration \u2014 the standard remediation used by lodash and others.\n\n### Workarounds\n\nAvoid passing JSON-parsed untrusted input through `commons._.merge`. Freezing `Object.prototype` or validating/sanitizing keys upstream also mitigates.\n\n### Credit\n\nReported responsibly by Andrew Ridings (@ridingsa).",
  "id": "GHSA-28xv-ph75-77wh",
  "modified": "2026-07-14T19:40:05Z",
  "published": "2026-07-14T19:40:05Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/feathersjs/feathers/security/advisories/GHSA-28xv-ph75-77wh"
    },
    {
      "type": "WEB",
      "url": "https://github.com/feathersjs/feathers/pull/3690"
    },
    {
      "type": "WEB",
      "url": "https://github.com/feathersjs/feathers/commit/28b3c03c63bdbff53115fdaa46c56980e7942acc"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/feathersjs/feathers"
    },
    {
      "type": "WEB",
      "url": "https://github.com/feathersjs/feathers/releases/tag/v5.0.45"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__"
}