Medium

Instant Popup Builder <= 1.1.7 - Unauthenticated Arbitrary Shortcode Execution via 'token' Parameter

  • Disclosed: 18.03.2026
  • Updated: 11.10.2026 10:22

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.

Affected software

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PlatformPackageVulnerable versionsFixed in
WordPress plugin Instant Popup Builder – Popup Maker for Videos, Forms, Offers, Announcements, Galleries & More <= 1.1.7 1.1.8

References

CVSS score 5.3/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness (CWE)
CWE-862
Platform
WordPress
Package
Instant Popup Builder – Popup Maker for Videos, Forms, Offers, Announcements, Galleries & More
Disclosed
18.03.2026
Updated
11.10.2026 10:22

Sources and licenses

Wordfence Intelligence - 979962e3-9052-4dc9-94d0-3ec8de3d5460 - Wordfence Intelligence

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Copyright 2012-2026 Defiant Inc.

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Wordfence Intelligence
Wordfence Intelligence - Defiant, Inc.
Copyright Defiant, Inc. All rights reserved except as granted below.
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Subject to this Agreement, Company hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute the Service. Any copy you make for such purposes is authorized provided that you reproduce Company’s copyright designation, this license, and the license of any disclosed Company licensor in any such copy.

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Vulnerability history: Instant Popup Builder – Popup Maker for Videos, Forms, Offers, Announcements, Galleries & More

All published vulnerabilities of this package (WordPress plugin), newest first. Shows whether this is a one-off slip or a package that needs watching.

This is the only known vulnerability of this package.

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