Instant Popup Builder <= 1.1.7 - Unauthenticated Arbitrary Shortcode Execution via 'token' Parameter
Summary
| CVE | CVE-2026-3475 |
|---|---|
| State | PUBLISHED |
| Assigner | Wordfence |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-19 08:16:19 UTC |
| Updated | 2026-04-22 21:32:08 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 5.3 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS: 0.000850000 probability, percentile 0.246000000 (date 2026-04-22)
Problem Types: CWE-862 | CWE-862 CWE-862 Missing Authorization
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
| 3.1 | CNA | DECLARED | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
LowAvailability
NoneCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Instantpopupbuilder | Instant Popup Builder Powerful Popup Maker For Opt-ins Email Newsletters Lead Generation | affected 1.1.7 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant... | [email protected] | plugins.trac.wordpress.org | |
| www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8d... | [email protected] | www.wordfence.com | |
| plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popu... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/changeset | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popu... | [email protected] | plugins.trac.wordpress.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Youcef Hamdani (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-03-03T17:15:24.000Z | Vendor Notified |
| CNA | 2026-03-18T19:02:53.000Z | Disclosed |
There are currently no legacy QID mappings associated with this CVE.