CleverTap Web SDK is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function

Description

CleverTap Web SDK version 1.15.2 and earlier is vulnerable to Cross-site Scripting (XSS) via window.postMessage. The handleCustomHtmlPreviewPostMessageEvent function in src/util/campaignRender/nativeDisplay.js performs insufficient origin validation using the includes() method, which can be bypassed by an attacker using a subdomain.

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-j5mf-6rh3-rhgg
• CVE-2026-26861
• CWE-346
• CWE-79
• CAPEC-310
• OWASP 2021-A3
• OWASP 2021-A6
• OWASP 2021-A7

Related Issues

• CleverTap Web SDK is vulnerable to DOM-based Cross-Site Scripting (XSS) via window.postMessage - CVE-2026-26862
• TeleJSON: DOM XSS via unsanitised constructor name in `new Function()` - CVE-2026-47099
• Svelte Vulnerable to XSS via DOM Clobbering of Internal Framework State - CVE-2026-42573
• SCEditor has DOM XSS via emoticon URL/HTML injection - CVE-2026-25581

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Tags:

npm

clevertap-web-sdk