Unauthenticated Arbitrary Shortcode Execution in Instant Popup Builder for WordPress
CVE-2026-3475

5.3MEDIUM

Key Information:

Vendor

WordPress
Status
Instant Popup Builder – Powerful Popup Maker For Opt-ins, Email Newsletters & Lead Generation
Vendor
CVE Published:
19 March 2026

What is CVE-2026-3475?

The Instant Popup Builder plugin for WordPress contains a vulnerability that allows unauthenticated users to exploit the plugin by executing arbitrary shortcodes. This issue arises due to improper sanitization of user-supplied GET parameters, specifically in the handle_email_verification_page() function. The function constructs a shortcode string without adequately handling square bracket characters, which leads to the premature closure of shortcode tags. Attackers can craft a malicious token parameter that includes special characters, enabling the injection and execution of arbitrary shortcode syntax. Administrators are advised to review and upgrade to the latest version to mitigate this risk.

Affected Version(s)

Instant Popup Builder – Powerful Popup Maker for Opt-ins, Email Newsletters & Lead Generation 0 <= 1.1.7

References

https://www.wordfence.com/threat-intel/vulnerabilities/id...
https://plugins.trac.wordpress.org/browser/instant-popup-...
https://plugins.trac.wordpress.org/browser/instant-popup-...

CVSS V3.1

Score:
5.3
Severity:
MEDIUM
Confidentiality:
None
Integrity:
Low
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Youcef Hamdani
.