CVE-2026-92781: BuilderIO @builder.io/sdk-react · Prototype Pollution
Affects BuilderIO @builder.io/sdk-reactSource CVE Database V5
Not known to be exploited · CVSS 5.3 Medium.
Data as of 1 Nov 2026, 11:03 UTC
- EPSS
- 0.3% chance of exploitation in 30 days – higher than 29% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| BuilderIO@builder.io/sdk-react | Affected
| Fixed in– |
| BuilderIO@builder.io/sdk-vue | Affected
| Fixed in– |
| BuilderIO@builder.io/sdk-svelte | Affected
| Fixed in– |
| BuilderIO@builder.io/sdk-solid | Affected
| Fixed in– |
| BuilderIO@builder.io/sdk-qwik | Affected
| Fixed in– |
| BuilderIO@builder.io/sdk-angular | Affected
| Fixed in– |
AI-suggested
Until a fix is available, avoid using untrusted or unvalidated preview links containing userAttributes query parameters. Implement input validation or sanitization to block __proto__ or prototype keys in query parameters if possible.
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.
References
- github.com/BuilderIO/builder/issues/4824 (opens in a new tab)
- github.com/BuilderIO/builder (opens in a new tab)
- github.com/BuilderIO/builder/blob/main/packages/sdks/src/functions/get-content/generate-content-url.ts (opens in a new tab)
- github.com/BuilderIO/builder/blob/main/packages/sdks/src/helpers/flatten.ts (opens in a new tab)
- vulncheck.com/advisories/builder-io-gen2-sdks-through-5.2.11-prototype-pollution-via-builder-userattributes (opens in a new tab)