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CVE

CVE-2026-26861

CleverTap Web SDK is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function
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CVE

CVE-2026-26861

CleverTap Web SDK is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function

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.

Package Versions Affected

Package Version
patch Availability
No items found.

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CVSS Version

Severity
Base Score
CVSS Version
Score Vector
C
H
U
8.3
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
C
H
U
0
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L
C
H
U
8.3
-
3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L

Related Resources

No items found.

References

https://nvd.nist.gov/vuln/detail/CVE-2026-26861, https://github.com/CleverTap/clevertap-web-sdk/issues/424, https://github.com/CleverTap/clevertap-web-sdk/pull/417, https://github.com/CleverTap/clevertap-web-sdk/commit/84695b726a751614ddc3a4f71382c239c5833e03, https://github.com/CleverTap/clevertap-web-sdk, https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121

Severity

8.3

CVSS Score
0
10

Basic Information

Ecosystem
Base CVSS
8.3
EPSS Probability
0.00009%
EPSS Percentile
0.01016%
Introduced Version
0,1.13.4
Fix Available
1.15.3

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