What’s Vulnerable › Vulnerabilities

CVE-2026-92781: Builder.io Gen2 SDKs through 5.2.11 Prototype Pollution via builder.userAttributes

• Severity: medium (CVSS 6.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-16 · updated 2026-09-24
• Weakness: CWE-1321

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.

Affected products

• BuilderIO @builder.io/sdk-angular: through 0.25.13
• BuilderIO @builder.io/sdk-qwik: through 0.25.13
• BuilderIO @builder.io/sdk-react: through 5.2.11
• BuilderIO @builder.io/sdk-react-nextjs: through 0.25.13
• BuilderIO @builder.io/sdk-solid: through 5.2.11
• BuilderIO @builder.io/sdk-svelte: through 5.2.11
• BuilderIO @builder.io/sdk-vue: through 5.2.11

References

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

Get alerted when CVE-2026-92781 or the next vulnerability affects your stack