CVE-2026-26862: CleverTap Web SDK is vulnerable to DOM-based Cross-Site Scripting (XSS) via window.postMessage
(updated )
CleverTap Web SDK version 1.15.2 and earlier is vulnerable to DOM-based Cross-Site Scripting (XSS) via window.postMessage in the Visual Builder module. The origin validation in src/modules/visualBuilder/pageBuilder.js (lines 56-60) uses the includes() method to verify the originUrl contains “dashboard.clevertap.com”, which can be bypassed by an attacker using a crafted subdomain.
References
- github.com/CleverTap/clevertap-web-sdk
- github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/modules/visualBuilder/pageBuilder.js
- github.com/CleverTap/clevertap-web-sdk/commit/766f75f0c9082a27eb0b59c9fa4b0d9b19ba3d10
- github.com/CleverTap/clevertap-web-sdk/commit/84695b726a751614ddc3a4f71382c239c5833e03
- github.com/CleverTap/clevertap-web-sdk/issues/442
- github.com/CleverTap/clevertap-web-sdk/pull/417
- github.com/advisories/GHSA-jfrq-hj9f-c8qx
- nvd.nist.gov/vuln/detail/CVE-2026-26862
Code Behaviors & Features
Detect and mitigate CVE-2026-26862 with GitLab Dependency Scanning
Secure your software supply chain by verifying that all open source dependencies used in your projects contain no disclosed vulnerabilities. Dependency Scanning using SBOM also detects vulnerabilities from proprietary advisories that this site does not include. Learn more about Dependency Scanning using SBOM →