CWE-1321 496 CVEs MITRE definition ↗

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

Overview

CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')) documents a weakness type used across vulnerability databases and security assessments. Use the sections below for definition, context, and mapped CVEs.

Security impact
Security impact: Depends on product and context; use CVE records, severity scores, and MITRE guidance to prioritize.

Description

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.

Applicable platforms

Kind Name Class Prevalence OS / CPE
language JavaScript Undetermined

Related CVEs in this database

These CVEs are mapped to this weakness in this database and kept for traceability and search.

CVE Published Summary
CVE-2026-44495 2026-06-11 Axios is a promise based HTTP client for the browser and Node.js. From 0.19.0 to before 0.31.1 and 1.15.2, Axios contains prototype-pollution gadgets in request config processing. If another vulnerabi…
CVE-2026-44494 2026-06-11 Axios is a promise based HTTP client for the browser and Node.js. From 1.0.0 to before 1.16.0, the Axios library is vulnerable to a Prototype Pollution "Gadget" attack that allows any Object.prototype…
CVE-2026-44490 2026-06-11 Axios is a promise based HTTP client for the browser and Node.js. Prior to 0.32.0 and 1.16.0, axios exposes two read-side prototype-pollution gadgets. When Object.prototype is polluted by an upstream …
CVE-2026-44489 2026-06-11 Axios is a promise based HTTP client for the browser and Node.js. From 1.15.2 to before 1.16.0, nested objects created by utils.merge() (e.g., config.proxy) are still constructed as plain {} with Obje…
CVE-2026-46625 2026-06-10 JavaScript Cookie is a JavaScript API for handling cookies, client-side. Prior to version 3.0.7, js-cookie's internal assign() helper copies properties with for...in + plain assignment. When the sourc…
CVE-2026-45302 2026-06-01 parse-nested-form-data is a tiny node module for parsing FormData by name into objects and arrays. Prior to version 1.0.1, parseFormData() walks bracket and dot-notation FormData field names into nest…
CVE-2026-46510 2026-05-29 form-data-objectizer converts FormData to object. Prior to 1.0.1, form-data-objectizer walks bracket-notation form keys (e.g. name[sub]) into nested objects without filtering __proto__, constructor, o…
CVE-2026-46509 2026-05-28 deepobj provides get, set, delete deep objects in javascript. Prior to 1.0.3, prototype pollution is possible when property paths contain __proto__/constructor/prototype. The property path must not be…
CVE-2026-44483 2026-05-27 RVF (formerly Remix Validated Form) provides easy form validation and state management for React. From 6.0.0 to before 6.0.4 and 7.0.2, setPath in @rvf/set-get (used by @rvf/core to flatten incoming f…
CVE-2026-44966 2026-05-26 Velocity.js is a JavaScript implementation of the Apache Velocity template engine. In 2.1.5 and earlier, a prototype pollution vulnerability was discovered in velocityjs. This issue occurs during the …
CVE-2026-9101 2026-05-20 Prototype pollution in csv parsing logic during import can lead to untrusted file paths (but not arguments) entering shell.openExternal after specific user behavior leading to "1-click" command execut…
CVE-2026-8657 2026-05-16 Versions of the package jsondiffpatch before 0.7.6 are vulnerable to Prototype Pollution via the jsondiffpatch.patch() and jsondiffpatch/formatters/jsonpatch.patch() APIs. An attacker can perform prot…
CVE-2026-44005 2026-05-13 vm2 is an open source vm/sandbox for Node.js. From 3.9.6 to 3.10.5, vm2's bridge exposes mutable proxies for real host-realm intrinsic prototypes and then forwards sandbox writes into the underlying h…
CVE-2026-44292 2026-05-13 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs generated message constructors copied enumerable properties from a provided properties obj…
CVE-2026-44290 2026-05-13 protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs allowed certain schema option paths to traverse through inherited object properties while …
CVE-2026-8161 2026-05-12 [email protected] and lower versions are vulnerable to denial of service via uncaught exception. By sending a multipart/form-data request with a field name that collides with an inherited Object.protot…
CVE-2026-41690 2026-05-08 18next-http-middleware is a middleware to be used with Node.js web frameworks like express or Fastify and also for Deno. Versions prior to 3.9.3 allow an unauthenticated HTTP client to pollute Object.…
CVE-2026-42264 2026-05-08 Axios is a promise based HTTP client for the browser and Node.js. From version 1.0.0 to before version 1.15.2, fFive config properties (auth, baseURL, socketPath, beforeRedirect, and insecureHTTPParse…
CVE-2025-63704 2026-05-07 NPM package query-parser-string 1.0.0 is vulnerable to Prototype Pollution. The package does not properly sanitize user supplied query parameters and merges them to the newly created object.
CVE-2025-63703 2026-05-07 npm package parse-ini v1.0.6 is vulnerable to Prototype Pollution in index.js().

Content submission

Name
Anonymous External Contributor
Date
2020-08-25
Version
4.3

Content modifications

Date Name Version Importance Comment
2021-10-28 CWE Content Team 4.6 updated Relationships
2023-01-31 CWE Content Team 4.10 updated Description
2023-04-27 CWE Content Team 4.11 updated Relationships
2023-06-29 CWE Content Team 4.12 updated Mapping_Notes
2024-02-29 CWE Content Team 4.14 updated Demonstrative_Examples
2025-09-09 CWE Content Team 4.18 updated Common_Consequences, Description, Diagram, Modes_of_Introduction
2025-12-11 CWE Content Team 4.19 updated Detection_Factors, Weakness_Ordinalities
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