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.

Weaknesses 1

References 6

• plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1761
• plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772
• plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1761
• plugins.trac.wordpress.org https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772
• plugins.trac.wordpress.org 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=
• wordfence.com https://www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8de3d5460?source=cve

Remediation