clevertap/clevertap-web-sdk · Security
CleverTap Web SDK is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function
- GHSA ID
- GHSA-j5mf-6rh3-rhgg
- CVE ID
- CVE-2026-26861
- Severity
- high
- Published
- Updated
- CVSS
- 8.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
- CVSS v3
- 8.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
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.
CWEs
- CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CWE-346 · Origin Validation Error
References
- https://nvd.nist.gov/vuln/detail/CVE-2026-26861 ↗
- https://github.com/CleverTap/clevertap-web-sdk/issues/424 ↗
- https://github.com/CleverTap/clevertap-web-sdk/pull/417 ↗
- https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121 ↗
- https://github.com/CleverTap/clevertap-web-sdk/commit/84695b726a751614ddc3a4f71382c239c5833e03 ↗
- https://github.com/advisories/GHSA-j5mf-6rh3-rhgg ↗