CVE-2026-92781CWE-1321

CVE-2026-92781

Medium · published September 17, 2026

CVSS v3.1
6.3
EPSS
0%
Percentile
28.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
6.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:L
CVSS v4.0
5.3 · 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
EPSS
0.00359 · 28.4th percentile
Weakness
CWE-1321 · Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
Published
2026-09-17T01:17Z
References (6)
https://github.com/BuilderIO/builder · [email protected]https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-content/generate-content-url.ts · [email protected]https://github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatten.ts#L60-L76 · [email protected]https://github.com/BuilderIO/builder/issues/4824 · [email protected]https://www.vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-prototype-pollution-via-builder-userattributes · [email protected]https://github.com/BuilderIO/builder/issues/4824 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 18 SEP 04:02Z
    EPSS moved — → 0%
    epss
  • 16 SEP 20:32Z
    Builder.io Gen2 SDKs through 5.2.11 Prototype Pollution via builder.userAttributes
    cvelistv5