CVE-2026-92781
Builder.io Gen2 SDKs through 5.2.11 Prototype Pollution via builder.userAttributes
- State
- Published
- Severity
- 5.3 Medium
- Published
- Sep 16, 2026
- Updated
- Sep 21, 2026
- Reserved
- Sep 16, 2026
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.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 5.3 Medium | 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 | VulnCheck |
| 3.1 | 6.3 Medium | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L | VulnCheck |
Weaknesses
- CWE-1321 Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Affected Products
| Product | Versions |
|---|---|
@builder.io/sdk-reactBuilderIO |
|
@builder.io/sdk-vueBuilderIO |
|
@builder.io/sdk-svelteBuilderIO |
|
@builder.io/sdk-solidBuilderIO |
|
@builder.io/sdk-qwikBuilderIO |
|
@builder.io/sdk-angularBuilderIO |
|
@builder.io/sdk-react-nextjsBuilderIO |
|
References
- GitHub Issue #4824issue-tracking
- https://github.com/BuilderIO/builderproduct
- builder.userAttributes parameters are expanded through unflattentechnical-description
- unflatten walks the dotted key path with no prototype guardtechnical-description
- VulnCheck Advisory: Builder.io Gen2 SDKs through 5.2.11 Prototype Pollution via builder.userAttributesthird-party-advisory
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