CVE-2026-3475: CWE-862 Missing Authorization in instantpopupbuilder Instant Popup Builder – Powerful Popup Maker for Opt-ins, Email Newsletters & Lead Generation
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.
AI Analysis
Technical Summary
CVE-2026-3475 is a missing authorization vulnerability (CWE-862) in the Instant Popup Builder WordPress plugin. The handle_email_verification_page() function constructs a shortcode string from user-supplied GET parameters (token, email) and passes it to do_shortcode() without sanitizing square bracket characters or performing authorization checks on the init hook. Because sanitize_text_field() and esc_attr() do not remove or escape square brackets, an attacker can prematurely close shortcode tags and inject arbitrary shortcodes. This allows unauthenticated arbitrary shortcode execution, potentially impacting plugin behavior or site functionality.
Potential Impact
An unauthenticated attacker can inject and execute arbitrary registered shortcodes in the vulnerable plugin, which may lead to unintended plugin or site behavior. The CVSS vector indicates no confidentiality or availability impact but a low integrity impact. There is no indication of known exploits in the wild.
Mitigation Recommendations
No official patch or fix is currently available for this vulnerability. Users should monitor the vendor's advisory for updates. Until a fix is released, consider disabling or restricting access to the affected plugin functionality if possible to reduce exposure.
CVE-2026-3475: CWE-862 Missing Authorization in instantpopupbuilder Instant Popup Builder – Powerful Popup Maker for Opt-ins, Email Newsletters & Lead Generation
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-3475 is a missing authorization vulnerability (CWE-862) in the Instant Popup Builder WordPress plugin. The handle_email_verification_page() function constructs a shortcode string from user-supplied GET parameters (token, email) and passes it to do_shortcode() without sanitizing square bracket characters or performing authorization checks on the init hook. Because sanitize_text_field() and esc_attr() do not remove or escape square brackets, an attacker can prematurely close shortcode tags and inject arbitrary shortcodes. This allows unauthenticated arbitrary shortcode execution, potentially impacting plugin behavior or site functionality.
Potential Impact
An unauthenticated attacker can inject and execute arbitrary registered shortcodes in the vulnerable plugin, which may lead to unintended plugin or site behavior. The CVSS vector indicates no confidentiality or availability impact but a low integrity impact. There is no indication of known exploits in the wild.
Mitigation Recommendations
No official patch or fix is currently available for this vulnerability. Users should monitor the vendor's advisory for updates. Until a fix is released, consider disabling or restricting access to the affected plugin functionality if possible to reduce exposure.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Wordfence
- Date Reserved
- 2026-03-03T13:12:45.335Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 69bbabafe32a4fbe5fa0f1a6
Added to database: 3/19/2026, 7:54:23 AM
Last enriched: 4/9/2026, 6:47:44 PM
Last updated: 5/2/2026, 9:51:22 AM
Views: 100
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