instantpopupbuilder Instant Popup Builder Plugin up to 1.1.7 on WordPress Token handle_email_verification_page token/email authorization

Summaryinfo

A vulnerability classified as critical was found in instantpopupbuilder Instant Popup Builder Plugin up to 1.1.7 on WordPress. Affected is the function handle_email_verification_page of the component Token Handler. Such manipulation of the argument token/email leads to authorization. This vulnerability is referenced as CVE-2026-3475. It is possible to launch the attack remotely. No exploit is available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in instantpopupbuilder Instant Popup Builder Plugin up to 1.1.7 on WordPress and classified as critical. Affected by this issue is the function handle_email_verification_page of the component Token Handler. The manipulation of the argument token/email with an unknown input leads to a authorization vulnerability. Using CWE to declare the problem leads to CWE-862. The product does not perform an authorization check when an actor attempts to access a resource or perform an action. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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.

The weakness was published by Youcef Hamdani. The advisory is shared for download at wordfence.com. This vulnerability is handled as CVE-2026-3475 since 03/03/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

Upgrading to version 1.1.6 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-13074). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

• WordPress Plugin

Vendor

• instantpopupbuilder

Name

• Instant Popup Builder Plugin

Version

• 1.1.0
• 1.1.1
• 1.1.2
• 1.1.3
• 1.1.4
• 1.1.5
• 1.1.6
• 1.1.7

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CPE 2.2info

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VulDB is the best source for vulnerability data and more expert information about this specific topic.

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