CVE-2026-26861

State: Published
Severity: 8.3 High
Published: Feb 27, 2026
Updated: Feb 27, 2026
Reserved: Feb 16, 2026

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

Scores

CVSS	Score	Vector	Source
3.1	8.3 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L	CISA-ADP

Weaknesses

CWE-346 Origin Validation Error

Affected Products

Product	Versions
n/an/a	n/aAffected

References

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

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