CVE-2026-26861

HIGH

8.3

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

CVE Details

CVSS v3.1 Score8.3

SeverityHIGH

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

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionREQUIRED

Published2/27/2026

Last Modified3/3/2026

Sourcenvd

Honeypot Sightings0

Affected Products

clevertap:clevertap_web_sdk

Weaknesses (CWE)

CWE-346

References

https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121(cve@mitre.org)

https://github.com/CleverTap/clevertap-web-sdk/issues/424(cve@mitre.org)

https://github.com/CleverTap/clevertap-web-sdk/pull/417(cve@mitre.org)

IOC Correlations

No correlations recorded

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