Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') Affecting node-deepmerge package, versions *


Severity

Recommended
0.0
high
0
10

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Threat Intelligence

EPSS
0.36% (30th percentile)

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  • Snyk IDSNYK-ECHOLATEST-NODEDEEPMERGE-19946197
  • published19 Sept 2026
  • disclosed18 Sept 2026

Introduced: 18 Sep 2026

NewCVE-2026-93753  (opens in a new tab)
CWE-1321  (opens in a new tab)

How to fix?

There is no fixed version for Echo:latest node-deepmerge.

NVD Description

Note: Versions mentioned in the description apply only to the upstream node-deepmerge package and not the node-deepmerge package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

deepmerge through 4.3.1 contains a prototype poisoning vulnerability in the mergeObject() function that fails to properly validate keys being written to target objects. Attackers can supply malicious source objects in merge operations to inject attacker-controlled properties into the returned object's prototype, causing applications to inherit unintended values when accessing properties without own-property checks.

CVSS Base Scores

version 3.1