{"id":"CVE-2026-26861","aliases":["GHSA-j5mf-6rh3-rhgg"],"url":"https://o3.security/vulnerability/CVE-2026-26861","summary":"CleverTap Web SDK  is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function","details":"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","published":"2026-02-27T00:00:00Z","modified":"2026-08-12T03:51:33.780694778Z","cvss":{"score":8.3,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"npm","name":"clevertap-web-sdk","fixedVersion":"1.15.3"}],"fix":{"url":"https://github.com/CleverTap/clevertap-web-sdk/pull/417","label":"CleverTap/clevertap-web-sdk#417"},"references":[{"type":"WEB","url":"https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/26xxx/CVE-2026-26861.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-26861"},{"type":"REPORT","url":"https://github.com/CleverTap/clevertap-web-sdk/issues/424"},{"type":"FIX","url":"https://github.com/CleverTap/clevertap-web-sdk/pull/417"},{"type":"WEB","url":"https://github.com/CleverTap/clevertap-web-sdk/commit/84695b726a751614ddc3a4f71382c239c5833e03"},{"type":"PACKAGE","url":"https://github.com/CleverTap/clevertap-web-sdk"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-12T03:51:33.780694778Z"}}