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Low 3.7Published Jul 17, 2026

CVE-2026-54335Feathersjs: Prototype pollution in @feathersjs/commons _.merge via JSON-parsed __proto__

Updated under an hour ago ()

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It affects feathersjs feathers. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-1321
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Jul 20, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
feathersjs feathers
feathersjs:feathers (from the name)
before 5.0.45
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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