CVE-2026-26862

Severity: high (CVSS 8.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-02-27 · updated 2026-06-17
Weakness: CWE-79

Description

CleverTap Web SDK version 1.15.2 and earlier is vulnerable to DOM-based Cross-Site Scripting (XSS) via window.postMessage in the Visual Builder module. The origin validation in src/modules/visualBuilder/pageBuilder.js (lines 56-60) uses the includes() method to verify the originUrl contains "dashboard.clevertap.com", which can be bypassed by an attacker using a crafted subdomain

Affected products

Clevertap Web Sdk: through 1.15.2

References

https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/modules/visualBuilder/pageBuilder.js#L56-L60
https://github.com/CleverTap/clevertap-web-sdk/issues/442
https://github.com/CleverTap/clevertap-web-sdk/pull/417

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