CVE-2026-92781

Published: Sep 16, 2026Modified: Sep 24, 2026Deferred

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XShow less

Source: disclosure@vulncheck.com (Secondary)

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.

Related CWEs

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.

References (6)

https://github.com/BuilderIO/builder

Source: disclosure@vulncheck.com

https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-content/generate-content-url.ts

Source: disclosure@vulncheck.com

https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatten.ts#L60-L76

Source: disclosure@vulncheck.com

https://github.com/BuilderIO/builder/issues/4824

Source: disclosure@vulncheck.com

https://www.vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-prototype-pollution-via-builder-userattributes

Source: disclosure@vulncheck.com

https://github.com/BuilderIO/builder/issues/4824

Source: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Timeline

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