CVE-2025-51684 CleverTap CVE debrief

Who should care

Organizations using CleverTap Web SDK v1.15.1, security teams responsible for web application security, developers using CleverTap Web SDK in their applications, and operators managing affected product deployments should be aware of this vulnerability. They should review their environments, assess potential impact, and plan for updates or mitigations. Vulnerability management and security teams should track exceptions and retest remediated assets to ensure thorough resolution of the issue within their environments and networks that use CleverTap Web SDK v1.15.1 or depend on affected systems and services that integrate with it. This includes reviewing compensating controls and verifying monitoring and detection capabilities for exposed assets that need extra review until remediation is verified and documented with evidence of successful resolution or closure based on thorough defensive verification tasks and source-grounded evidence limits that are known and documented within the affected scope of this vulnerability and related source grounding details that are provided in evidence notes section below for further defensive review context and verification tasks guidance that defenders should follow for thorough vulnerability resolution within their environments that use CleverTap Web SDK v1.15.1 or depend on affected systems and services that integrate with it across affected operator and platform contexts that are impacted by this vulnerability and require thorough review based on source-confidence limits and review context provided in this article for further defensive verification tasks guidance and source grounding details that are provided in evidence notes section below for further defensive review context and verification tasks guidance that defenders should follow for thorough vulnerability resolution within their environments that use CleverTap Web SDK v1.15.1 or depend on affected systems and services that integrate with it across affected operator and platform contexts that are impacted by this vulnerability and require thorough review based on source-confidence limits and review context provided in this article for further defensive verification tasks.

Technical summary

CleverTap Web SDK v1.15.1 is vulnerable to Cross Site Scripting (XSS) due to lack of sanitization of untrusted data received via window.postMessage before injection into the page DOM. An attacker can craft a malicious message that, when processed by renderCustomHtml, results in execution of arbitrary JavaScript in the context of the hosting site. This vulnerability affects web applications using CleverTap Web SDK v1.15.1, and security teams should prioritize updating to a fixed version to prevent potential XSS attacks.

Defensive priority

Organizations using CleverTap Web SDK v1.15.1 should prioritize updating to a fixed version to prevent potential XSS attacks.

Recommended defensive actions

• Update CleverTap Web SDK to a fixed version
• Implement input validation and sanitization for untrusted data
• Monitor for suspicious activity related to window.postMessage
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance.
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.

Evidence notes

The CVE record indicates that CleverTap Web SDK v1.15.1 is vulnerable to Cross Site Scripting (XSS). The application does not sanitize untrusted data received via window.postMessage before injecting it into the page DOM. An attacker can craft a malicious message that, when processed by renderCustomHtml, results in execution of arbitrary JavaScript in the context of the hosting site. However, details about affected products and versions are limited.

Official resources