---
id: CVE-2026-92781
title: >-
  Builder.io Gen2 SDKs through versions 5.2.11 and 0.25.13 contain a prototype
  pollution vulnerability in the unflatten helper that processes
  builder.userAttributes query parameters without prototype guards
summary: >-
  Builder.io Gen2 SDKs through versions 5.2.11 and 0.25.13 contain a prototype
  pollution vulnerability in the unflatten helper that processes
  builder.userAttributes query parameters without prototype guards. Attackers
  can craft preview lin…
severity: medium
cvss: 6.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'
cwe:
  - CWE-1321
vendor: BuilderIO
product: '@builder.io/sdk-react'
affected:
  - '@builder.io/sdk-react <= 5.2.11'
  - '@builder.io/sdk-vue <= 5.2.11'
  - '@builder.io/sdk-svelte <= 5.2.11'
  - '@builder.io/sdk-solid <= 5.2.11'
  - '@builder.io/sdk-qwik <= 0.25.13'
  - '@builder.io/sdk-angular <= 0.25.13'
  - '@builder.io/sdk-react-nextjs <= 0.25.13'
published: '2026-09-16'
updated: '2026-09-24'
sourceUpdated: '2026-09-24T21:08:55.030'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-92781'
references:
  - url: 'https://github.com/BuilderIO/builder'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-content/generate-content-url.ts
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatten.ts#L60-L76
    label: disclosure@vulncheck.com
  - url: 'https://github.com/BuilderIO/builder/issues/4824'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-prototype-pollution-via-builder-userattributes
    label: disclosure@vulncheck.com
  - url: 'https://github.com/BuilderIO/builder/issues/4824'
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - cve.org
  - exploit-available
epss: 0.00359
epssPercentile: 0.26989
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-21T15:50:07.571574Z'
ingestedAt: '2026-09-16T21:05:36.890Z'
---

## Overview

Builder.io Gen2 SDKs through versions 5.2.11 and 0.25.13 contain a prototype pollution vulnerability in the unflatten helper that processes builder.userAttributes query parameters without prototype guards. Attackers can craft preview links with __proto__ or prototype segments to pollute Object.prototype in a visitor's browser when the SDK processes the malicious URL.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.