Common Weakness Enumeration

    CWE Definition / CWE-1321

    CWE-1321: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')

    The product receives input from an upstream component that specifies attributes that are to be initialized or updated in an object, but it does not properly control modifications of attributes of the object prototype.

    Published:25 Aug 2020
    Organization:MITRE
    Modified:11 Dec 2025

    Related Weakness

    CWE-915: Improperly Controlled Modification of Dynamically-Determined Object Attributes

    CWE-913: Improper Control of Dynamically-Managed Code Resources

    CWE-471: Modification of Assumed-Immutable Data (MAID)