CVE-2026-54335

Feathersjs: Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__

Published Jul 17, 2026 CVSS 3.1 · 3.7 Low EPSS < 1% KEV · Not listed
Description
Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In 5.0.44 and earlier, the _.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__, constructor, or prototype key, that key is returned as an own-enumerable property; the recursive merge then resolves target['__proto__'] to Object.prototype and writes attacker-supplied properties onto it, polluting the prototype for all plain objects in the process for the lifetime of the Node process. This issue is fixed in version 5.0.45.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-28xv-ph75-77wh Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Feathersjs
Feathersjs feathers
Vendors & Products Feathersjs
Feathersjs feathers
Type Values Removed Values Added
Description Feathersjs is a framework for creating web APIs and real-time applications with TypeScript or JavaScript. In 5.0.44 and earlier, the _.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__, constructor, or prototype key, that key is returned as an own-enumerable property; the recursive merge then resolves target['__proto__'] to Object.prototype and writes attacker-supplied properties onto it, polluting the prototype for all plain objects in the process for the lifetime of the Node process. This issue is fixed in version 5.0.45.
Title Feathersjs: Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__
Weaknesses CWE-1321
References
Metrics cvssV3_1

{'score': 3.7, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Jul 20, 2026, 5:38 PM
Reserved
Jun 12, 2026, 7:23 PM
Status
Deferred
Published
Jul 17, 2026, 10:17 PM
Modified
Oct 24, 2026, 8:10 PM