CVE-2026-54335 feathersjs CVE debrief

Who should care

Developers and administrators using Feathersjs framework versions 5.0.44 and earlier should be aware of this vulnerability and take necessary actions to mitigate it. They should review and validate input data, implement additional security measures to prevent prototype pollution, and update to version 5.0.45 or later.

Technical summary

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.

Defensive priority

Low

Recommended defensive actions

• Update to version 5.0.45 or later
• Review and validate input data
• Implement additional security measures to prevent prototype pollution
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented

Evidence notes

The CVE record was published on 2026-07-17T22:17:44.840Z and has not been modified since then. The NVD entry is currently 3.7 (Low). The vulnerability affects Feathersjs framework versions 5.0.44 and earlier. Developers should verify their deployments and review official advisories for affected scope and severity.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.