CleverTap Web SDK is vulnerable to DOM-based Cross-Site Scripting (XSS) via window.postMessage

Description

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.

Recommendation

Update the clevertap-web-sdk package to the latest compatible version. Followings are version details:

• Affected version(s): < 1.15.3
• Patched version(s): 1.15.3

References

• GHSA-jfrq-hj9f-c8qx
• CVE-2026-26862
• CWE-79
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6

Related Issues

• CleverTap Web SDK is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function - CVE-2026-26861
• Parse Server vulnerable to stored cross-site scripting (XSS) via SVG file upload - CVE-2026-30948
• jsondiffpatch is vulnerable to Cross-site Scripting (XSS) via HtmlFormatter::nodeBegin - CVE-2025-9910
• QuestDB UI's Web Console is Vulnerable to Cross-Site Scripting - CVE-2026-0824

Tags:

npm

clevertap-web-sdk