Vulnerability · Published Mar 19, 2026 · Assigned by Wordfence

CVE-2026-3475Instant Popup Builder <= 1.1.7 - Unauthenticated Arbitrary Shortcode Execution via 'token' Parameter

Medium 5.3

In plain English

A medium-severity missing authorization in Instant Popup Builder – Powerful Popup Maker for Opt-ins, Email Newsletters & Lead Generation from instantpopupbuilder. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities).

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.3%top 77.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
instantpopupbuilder	Instant Popup Builder – Powerful Popup Maker for Opt-ins, Email Newsletters & Lead Generation	0 – through 1.1.7

Weakness: CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

In plain English

Official description

Affected products (as reported)

References