CVE-2026-92781

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.

  • Published Sep 16, 2026
  • CVSS 5.3 medium
  • 0.4% chance of exploitation in the next 30 days (EPSS)

Affected software

CVE-2026-92781 at the National Vulnerability Database