CVE-2026-26861

high

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

References

https://github.com/CleverTap/clevertap-web-sdk/pull/417

https://github.com/CleverTap/clevertap-web-sdk/issues/424

https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121

Details

Source: Mitre, NVD

Published: 2026-02-27

Updated: 2026-03-02

Risk Information

CVSS v2

Base Score: 4.3

Vector: CVSS2#AV:N/AC:M/Au:N/C:N/I:P/A:N

Severity: Medium

CVSS v3

Base Score: 8.3

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L

Severity: High

EPSS

EPSS: 0.00016