{"cve":"CVE-2026-3475","nvd":{"published":"2026-03-19T08:16:19.327","modified":"2026-06-17T10:43:38.663","status":"Deferred","description":"The Instant Popup Builder plugin for WordPress is vulnerable to Unauthenticated Arbitrary Shortcode Execution in all versions up to and including 1.1.7. This is due to the handle_email_verification_page() function constructing a shortcode string from user-supplied GET parameters (token, email) and passing it to do_shortcode() without properly sanitizing square bracket characters, combined with missing authorization checks on the init hook. While sanitize_text_field() and esc_attr() are applied, neither function strips or escapes square bracket characters ([ and ]). WordPress's shortcode regex uses [^\\]\\/]* to match content inside shortcode tags, meaning a ] character in the token value prematurely closes the shortcode tag. This makes it possible for unauthenticated attackers to inject and execute arbitrary registered shortcodes by crafting a malicious token parameter containing ] followed by arbitrary shortcode syntax.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","score":5.3},"cwes":["CWE-862"],"references":["https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1761","https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772","https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1761","https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772","https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3477334%40instant-popup-builder&new=3477334%40instant-popup-builder&sfp_email=&sfph_mail="],"products":[],"source":"nvd","synced_at":"2026-10-19T22:26:19.218427112+00:00"},"epss":{"cve":"CVE-2026-3475","score":0.00289,"percentile":0.21513,"date":"2026-10-31"},"kev":null,"osv":[],"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."]}