PT-2026-26263 · Instantpopupbuilder · Instant Popup Builder – Powerful Popup Maker For Opt-Ins
Youcef Hamdani
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Published
2026-03-19
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Updated
2026-03-19
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CVE-2026-3475
CVSS v3.1
5.3
Medium
| AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
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.
Fix
Missing Authorization
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Weakness Enumeration
Related Identifiers
Affected Products
Instant Popup Builder – Powerful Popup Maker For Opt-Ins