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Vulnerabilities

Vulnerability · CVE-2026-26861

CleverTap Web SDK version 1.15.2 and earlier is vulnerable to Cross-Site Scripting (XSS) via window.postMessage.

Published Feb 27, 2026 · catalog updated Jun 17, 2026 · clevertap web sdk

Check if you run it

No confirmed exploitation is on record for CVE-2026-26861. EPSS is 0.23%. Act only if a listed version of clevertap web sdk is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High8.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.23%
Remediation
Version ranges on file
Affected products
cpe clevertap/clevertap web sdk · stated clevertap web sdk

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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe clevertap/clevertap web sdkversion unspecified
  • stated clevertap web sdk<= 1.15.2

How to fix CVE-2026-26861

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-26861. EPSS is 0.23%. Act only if a listed version of clevertap web sdk is installed.

Which versions are affected?

Compare what you have installed with clevertap web sdk <= 1.15.2. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-346. EPSS 0.23%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 27, 2026 · NIST NVD

    Detected

    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

  2. Jun 17, 2026 · NIST NVD

    Updated

    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

Sources

  • CVE.orgVulnerability recordCVE-2026-26861

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-26861

    30-day exploitation probability 0.2%

    first.org
  • NIST NVDVulnerability recordCVE-2026-26861

    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, w

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.