Weakness (CWE)
CWE-1321: Improperly Controlled Modification of Object Prototype Attributes
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.
How to prevent it (5 mitigations)
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Implementation
By freezing the object prototype first (for example, Object.freeze(Object.prototype)), modification of the prototype becomes impossible.
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Architecture and Design
By blocking modifications of attributes that resolve to object prototype, such as proto or prototype, this weakness can be mitigated.
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Implementation
When handling untrusted objects, validating using a schema can be used.
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Implementation
By using an object without prototypes (via Object.create(null) ), adding object prototype attributes by accessing the prototype via the special attributes becomes impossible, mitigating this weakness.
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Implementation
Map can be used instead of objects in most cases. If Map methods are used instead of object attributes, it is not possible to access the object prototype or modify it.
Source: MITRE CWE-1321
307 results · Clear filters · Feed
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High 7.5
Browserslist: Uncaught crash / prototype write via untrusted browserslist-stats.json custom stats (normalizeStats)
Browserslist is a configuration tool for sharing target browsers and Node.js versions between front-end tools. Prior to 4.28.7, normalizeStats() in node.js, reached unconditionally through getStat() and loadStat() on every browserslist() call, processes untru…
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High 7.1
n8n before 1.123.67 Prototype Pollution via Edit Fields
n8n before 1.123.67, 2.31.5, and 2.32.1 contains a prototype pollution vulnerability in the Edit Fields (Set) node. The node assigns output fields via a dot-notation path setter without restricting the field name, allowing an authenticated user to name a fiel…
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High 8.3
axios before 0.33.0 Prototype Pollution via Node HTTP adapter
axios in a Node.js deployment using the HTTP adapter can route requests through an attacker-controlled proxy. axios hardens merged request configuration by creating a null-prototype object, but request interceptors run after the merge; a common immutable inte…
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High 7.3
@phun-ky/defaults-deep Has a Prototype Pollution issue via Unsafe Recursive Property Merging
@phun-ky/defaults-deep is a library like lodash defaultsDeep with array preservation and no lodash dependency. Prior to 2.0.5, defaultsDeep() recursively merges user-supplied objects without filtering proto, constructor, and prototype, allowing properties to …
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High 7.5
find-my-way is Vulnerable to DDoS with HTTP2
find-my-way is a framework-independent HTTP router that internally uses a Radix Tree and supports route parameters and wildcards. Versions prior to 9.7.0 are vulnerable to remotely triggerable DoS in find-my-way when it is used with Node's HTTP/2 server. The …
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High 7.3
IBM Instana Observability is affected by multiple Prototype Pollution within Instana Agent container image
IBM Observability with Instana (Agent) Build 1.0.303 through 1.0.320 IBM Instana Node.js tracer component @instana/core version 6.2.1 is vulnerable to prototype pollution through its configuration normalization API.
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High 7.2
@nevware21/ts-utils: Prototype Pollution in objDeepCopy/objCopyProps via for...in without hasOwnProperty
@nevware21/ts-utils is a comprehensive TypeScript/JavaScript utility library. Prior to version 0.14.0, the _copyProps function in lib/src/object/copy.ts uses for...in to iterate over source object properties without an Object.hasOwnProperty check, and does no…
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High 8.2
Gestor de Oferta: Prototype pollution in @tmlmobilidade/utils setValueAtPath
Gestor de Oferta is a web application for managing mobility service offerings. Prior to 20260509.0340.15, @tmlmobilidade/utils has a prototype pollution vulnerability in setValueAtPath() in packages/utils/src/generic/value-at-path.ts because unsafe path segme…
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High 8.6
Incomplete fix for CVE-2026-25754 in @adonisjs/bodyparser
AdonisJS is a TypeScript-first web framework. From 10.1.3 until 10.1.5 and 11.0.3, AdonisJS @adonisjs/bodyparser incompletely fixed CVE-2026-25754 because nested multipart field payloads such as user.__proto__.polluted and constructor.prototype still caused l…
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High 7.1
n8n: Prototype Pollution via Workflow Credentials Leads to Unauthenticated User and Project Enumeration
n8n is an open source workflow automation platform. Prior to 1.123.61, 2.27.4, and, 2.28.1, an authenticated user with the default workflow:create permission could pollute Object.prototype through a crafted workflow saved, updated, or imported via the workflo…
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High 8.8
Style Dictionary - Prototype Pollution in convertTokenData utility function
Style Dictionary, a build system for creating cross-platform styles, has a prototype pollution vulnerability starting in version 4.3.0 and prior to version 5.4.4. Impact users have: direct usage of `convertTokenData(tokens, { output: 'object' });`; indirect u…
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High 7.2
n8n: Microsoft SQL Node Prototype Pollution
n8n is an open source workflow automation platform. Prior to 2.24.0, an authenticated user with permission to create or modify workflows could achieve global prototype pollution via the Microsoft SQL node by supplying a crafted value as the table parameter. T…
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High 8.1
piscina: Prototype Pollution Gadget → RCE via inherited options.filename
piscina is a node.js worker pool implementation. Prior to 6.0.0-rc.2, 5.2.0, and 4.9.3, piscina's constructor and run() paths read the filename option via plain member access. Both reads fall through the prototype chain when the caller's options object doesn'…
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High 7.2
ThingsBoard contains a prototype pollution vulnerability which may lead to arbitrary code execution within a sandboxed …
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High 7.0
Axios: Credential Theft and Response Hijacking via Prototype Pollution Gadget in Config Merge
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 vulnerability in the same JavaScript process has already polluted Ob…
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High 8.7
Axios: Full Man-in-the-Middle via Prototype Pollution Gadget in `config.proxy`
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 pollution in the application's dependency tree to be escal…
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High 7.5
JavaScript Cookie: Per-instance prototype hijack in assign() enables cookie-attribute injection
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 source object is produced by JSON.parse, the JSON object's "__pr…
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High 8.2
Prototype Pollution in parse-nested-form-data via `__proto__` in FormData field names
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 nested objects without filtering reserved property keys. A sing…
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High 8.2
Prototype pollution in form-data-objectizer via bracket-notation form keys
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, or prototype. A single HTTP form field whose name starts wit…
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High 8.2
deepobj: Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
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 exposed as user input. This vulnerability is fixed in 1.0.…
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High 8.2
RVF: Prototype pollution in @rvf/set-get reachable via @rvf/core preprocessFormData (HTTP form data)
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 form data into a nested object) does not block the keys __pr…
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High 8.3
Velocity.js: Prototype Pollution in #set path assignment
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 processing of #set directives in Velocity templates. If an …
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High 8.2
jsondiffpatch patch APIs are vulnerable to prototype pollution
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 prototype pollution by supplying crafted delta or JSON Patch do…
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High 8.1
protobufjs: Code generation gadget after prototype pollution
protobufjs compiles protobuf definitions into JavaScript (JS) functions. Prior to 7.5.6 and 8.0.2, protobufjs used plain objects with inherited prototypes for internal type lookup tables used by generated encode and decode functions. If Object.prototype had a…
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High 7.5
protobufjs: Process-wide denial of service through unsafe option paths
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 applying options. A crafted protobuf schema or JSON descrip…
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High 7.5CVE-2026-8161 Public exploit
multiparty vulnerable to Denial of Service via Prototype Pollution leading to Uncaught Exception
multiparty@4.2.3 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.prototype property such as __proto__, constructor, or toString, t…
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High 7.5
@theecryptochad/merge-guard has Prototype Pollution in its deepMerge() function
## Summary `@theecryptochad/merge-guard` versions prior to 1.0.1 are vulnerable to Prototype Pollution via the `deepMerge()` function. An attacker who controls the source object can inject `__proto__` keys that mutate `Object.prototype`, affecting all objects…
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High 8.6
Prototype pollution and path traversal in i18next-http-middleware via user-controlled language and namespace parameters
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.prototype in the Node.js process hosting the middleware, vi…
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High 7.4
Axios: Prototype pollution read-side gadgets in HTTP adapter allow credential injection and request hijacking
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 insecureHTTPParser) in the HTTP adapter are read via direct property access …
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High 7.4
Axios: Header Injection via Prototype Pollution
Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, a prototype pollution gadget exists in the Axios HTTP adapter (lib/adapters/http.js) that allows an attacker to inject arbitrary HTTP headers into outgoing requests.…
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High 7.4
Axios: Prototype Pollution Gadgets - Response Tampering, Data Exfiltration, and Request Hijacking
Axios is a promise based HTTP client for the browser and Node.js. Prior to 1.15.1 and 0.31.1, when Object.prototype has been polluted by any co-dependency with keys that axios reads without a hasOwnProperty guard, an attacker can (a) silently intercept and mo…
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High 7.3
1024bit extend-deep index.js prototype pollution
A vulnerability was determined in 1024bit extend-deep up to 0.1.6. The impacted element is an unknown function of the file index.js. This manipulation of the argument __proto__ causes improperly controlled modification of object prototype attributes. Remote e…
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High 7.3
brikcss merge prototype pollution
A vulnerability was determined in brikcss merge up to 1.3.0. This affects an unknown part. Executing a manipulation of the argument __proto__/constructor.prototype/prototype can lead to improperly controlled modification of object prototype attributes. The at…
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High 8.6
Acrobat Reader | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (CWE-1321)
Acrobat Reader versions 26.001.21411, 24.001.30360, 24.001.30362 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the contex…
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High 8.6
Acrobat Reader | Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') (CWE-1321)
Acrobat Reader versions 24.001.30356, 26.001.21367 and earlier are affected by an Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution') vulnerability that could result in arbitrary code execution in the context of the curre…
KEV Apr 13, 2026 -
High 7.5
defu: Prototype pollution via `__proto__` key in defaults argument
defu is software that allows uers to assign default properties recursively. Prior to version 6.1.5, applications that pass unsanitized user input (e.g. parsed JSON request bodies, database records, or config files from untrusted sources) as the first argument…
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High 8.3
MikroORM has Prototype Pollution in Utils.merge
MikroORM is a TypeScript ORM for Node.js based on Data Mapper, Unit of Work and Identity Map patterns. Prior to versions 6.6.10 and 7.0.6, a prototype pollution vulnerability exists in the Utils.merge helper used internally by MikroORM when merging object str…
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High 8.9
flatted: Prototype Pollution via parse()
flatted is a circular JSON parser. Prior to version 3.4.2, the parse() function in flatted can use attacker-controlled string values from the parsed JSON as direct array index keys, without validating that they are numeric. Since the internal input buffer is …
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High 7.5
Qwik has array method pollution in FormData processing, allowing type confusion and DoS
Qwik is a performance-focused JavaScript framework. Versions prior to 1.19.2 improperly inferred arrays from dotted form field names during FormData parsing. By submitting mixed array-index and object-property keys for the same path, an attacker could cause u…
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High 8.2
Parse Server's Cloud function dispatch crashes server via prototype chain traversal
Parse Server is an open source backend that can be deployed to any infrastructure that can run Node.js. Prior to 9.6.0-alpha.24 and 8.6.47, remote clients can crash the Parse Server process by calling a cloud function endpoint with a crafted function name tha…