{"cve":"CVE-2026-26861","nvd":{"published":"2026-02-27T18:16:12.043","modified":"2026-06-17T10:26:21.957","status":"Analyzed","description":"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","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:L","score":8.3},"cwes":["CWE-346"],"references":["https://github.com/CleverTap/clevertap-web-sdk/blob/cf1b65d/src/util/campaignRender/nativeDisplay.js#L118-L121","https://github.com/CleverTap/clevertap-web-sdk/issues/424","https://github.com/CleverTap/clevertap-web-sdk/pull/417"],"products":["clevertap:clevertap_web_sdk"],"source":"nvd","synced_at":"2026-10-19T22:24:17.937441719+00:00"},"epss":{"cve":"CVE-2026-26861","score":0.00205,"percentile":0.10536,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-j5mf-6rh3-rhgg","url":"https://osv.dev/vulnerability/GHSA-j5mf-6rh3-rhgg","summary":"CleverTap Web SDK  is vulnerable to DOM-based XSS via handleCustomHtmlPreviewPostMessageEvent function","modified":"2026-03-04T15:12:09.217040Z","packages":[{"ecosystem":"npm","name":"clevertap-web-sdk","purl":"pkg:npm/clevertap-web-sdk","ranges":["<1.15.3"],"fixed":["1.15.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}