CVE-2026-26861
Received Received - Intake
Cross-Site Scripting in CleverTap Web SDK via postMessage

Publication date: 2026-02-27

Last updated on: 2026-03-03

Assigner: MITRE

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
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Meta Information
Published
2026-02-27
Last Modified
2026-03-03
Generated
2026-06-16
AI Q&A
2026-02-27
EPSS Evaluated
2026-06-15
NVD
CVE-2026-26861
EUVD
EUVD-2026-9038
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
clevertap clevertap_web_sdk to 1.15.2 (inc)
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-346 The product does not properly verify that the source of data or communication is valid.
Attack-Flow Graph
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Executive Summary

CleverTap Web SDK version 1.15.2 and earlier contains a Cross-Site Scripting (XSS) vulnerability via the window.postMessage API. Specifically, the function handleCustomHtmlPreviewPostMessageEvent in the file src/util/campaignRender/nativeDisplay.js does not properly validate the origin of messages. It uses the includes() method for origin validation, which can be bypassed by an attacker using a subdomain, allowing malicious scripts to be executed.

Impact Analysis

This vulnerability can allow an attacker to execute malicious scripts in the context of the affected web application. This can lead to unauthorized actions such as stealing user data, session hijacking, or performing actions on behalf of the user without their consent.

Compliance Impact

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Detection Guidance

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Mitigation Strategies

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