Vulnerability · Published Jul 17, 2026 · Assigned by GitHub_M
CVE-2026-54335Feathersjs: Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__
Low 3.7
In plain English
A low-severity prototype pollution in feathers from feathersjs. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @feathersjs/commons | 5.0.45 | GHSA-28xv-ph75-77wh |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| feathersjs | feathers | < 5.0.45 |
Weakness: CWE-1321 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
References
- https://github.com/feathersjs/feathers/security/advisories/GHSA-28xv-ph75-77wh x_refsource_CONFIRM
- https://github.com/feathersjs/feathers/pull/3690 x_refsource_MISC
- https://github.com/feathersjs/feathers/commit/28b3c03c63bdbff53115fdaa46c56980e7942acc x_refsource_MISC
- https://github.com/feathersjs/feathers/releases/tag/v5.0.45 x_refsource_MISC