VulnerabilityAnalyzed

CVE-2026-26862

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.

HIGH 8.3EPSS 0.37%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.37%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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

CVSS 3.1: 8.3 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
EPSS: 0.37% probability · 30th percentile
CISA KEV: Not listed
Weakness: CWE-79, CWE-829
Affected: clevertap/clevertap web sdk
Source: cve@mitre.org

References

https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/modules/visualBuilder/pageBuilder.js#L56-L60Product
https://github.com/CleverTap/clevertap-web-sdk/issues/442Exploit, Issue Tracking, Vendor Advisory
https://github.com/CleverTap/clevertap-web-sdk/pull/417Patch

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.