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.

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction Passive

Vulnerable System Confidentiality Impact Low

Vulnerable System Integrity Impact Low

Vulnerable System Availability Impact Low

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact Low

Integrity Impact Low

Availability Impact Low

User Interaction Required

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
BuilderIO @builder.io/sdk-react unaffected
Version Status Constraints
0 affected ≤ 5.2.11
BuilderIO @builder.io/sdk-vue unaffected
Version Status Constraints
0 affected ≤ 5.2.11
BuilderIO @builder.io/sdk-svelte unaffected
Version Status Constraints
0 affected ≤ 5.2.11
BuilderIO @builder.io/sdk-solid unaffected
Version Status Constraints
0 affected ≤ 5.2.11
BuilderIO @builder.io/sdk-qwik unaffected
Version Status Constraints
0 affected ≤ 0.25.13
BuilderIO @builder.io/sdk-angular unaffected
Version Status Constraints
0 affected ≤ 0.25.13
BuilderIO @builder.io/sdk-react-nextjs unaffected
Version Status Constraints
0 affected ≤ 0.25.13

No data.

No data.

No data.

Project Subscriptions

No data.

Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

References
Link Providers
https://github.com/BuilderIO/builder cve-icon cve-icon
https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-content/generate-content-url.ts cve-icon cve-icon
https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatten.ts#L60-L76 cve-icon cve-icon
https://github.com/BuilderIO/builder/issues/4824 cve-icon cve-icon
https://www.vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-prototype-pollution-via-builder-userattributes cve-icon cve-icon
History

Wed, 16 Sep 2026 20:45:00 +0000

Type Values Removed Values Added
Description 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.
Title Builder.io Gen2 SDKs through 5.2.11 Prototype Pollution via builder.userAttributes
Weaknesses CWE-1321
References
Metrics cvssV3_1

{'score': 6.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L'}

cvssV4_0

{'score': 5.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N'}

Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: VulnCheck

Published:

Updated: 2026-09-16T20:32:38.923Z

Reserved: 2026-09-16T19:22:53.825Z

Link: CVE-2026-92781

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-16T21:17:27.130

Modified: 2026-09-16T21:17:27.130

Link: CVE-2026-92781

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses