GHSA-gcqx-w48m-w2h4

    Dashboard / Vulnerabilities / GHSA-gcqx-w48m-w2h4

    GHSA-gcqx-w48m-w2h4

    Published: 18 Sept 2026Last Modified: 27 Oct 2026

    Summary: deepmerge mergeObject() allows prototype poisoning of returned objects

    Details: 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.

    References: https://nvd.nist.gov/vuln/detail/CVE-2026-93753, https://github.com/TehShrike/deepmerge/issues/273, https://github.com/TehShrike/deepmerge, https://github.com/TehShrike/deepmerge/blob/5b87756a5671635679001cbac72aa42f23472c81/index.js#L39-L60, https://www.vulncheck.com/advisories/deepmerge-through-4.3.1-prototype-poisoning-via-mergeobject

    Affected packages

    Package

    Name: deepmerge

    Purl: pkg:npm/deepmerge

    Affected ranges

    Type: SEMVER

    Events:

    Introduced- 4.2.0
    Fixed -None

    Affected versions

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    GHSA-gcqx-w48m-w2h4 | CVE-DB