FKIE_CVE-2026-3475
Vulnerability from fkie_nvd - Published: 2026-03-19 08:16 - Updated: 2026-06-17 10:43
Severity
Summary
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.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Instant Popup Builder \u2013 Powerful Popup Maker for Opt-ins, Email Newsletters \u0026 Lead Generation",
"vendor": "instantpopupbuilder",
"versions": [
{
"lessThanOrEqual": "1.1.7",
"status": "affected",
"version": "0",
"versionType": "semver"
}
]
}
],
"source": "security@wordfence.com"
}
],
"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\u0027s 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 Ejecuci\u00f3n Arbitraria de Shortcode No Autenticada en todas las versiones hasta la 1.1.7 inclusive. Esto se debe a que la funci\u00f3n handle_email_verification_page() construye una cadena de shortcode a partir de par\u00e1metros 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 autorizaci\u00f3n 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 expresi\u00f3n regular de shortcode de WordPress utiliza [^\\]\\/]* para hacer coincidir el contenido dentro de las etiquetas de shortcode, lo que significa que un car\u00e1cter ] 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 par\u00e1metro de token malicioso que contenga ] seguido de sintaxis de shortcode arbitraria."
}
],
"id": "CVE-2026-3475",
"lastModified": "2026-06-17T10:43:38.663",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 5.3,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "LOW",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
"version": "3.1"
},
"exploitabilityScore": 3.9,
"impactScore": 1.4,
"source": "security@wordfence.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2026-3475",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-03-19T13:44:02.852369Z",
"version": "2.0.3"
}
}
]
},
"published": "2026-03-19T08:16:19.327",
"references": [
{
"source": "security@wordfence.com",
"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1761"
},
{
"source": "security@wordfence.com",
"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772"
},
{
"source": "security@wordfence.com",
"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1761"
},
{
"source": "security@wordfence.com",
"url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772"
},
{
"source": "security@wordfence.com",
"url": "https://plugins.trac.wordpress.org/changeset?sfp_email=\u0026sfph_mail=\u0026reponame=\u0026old=3477334%40instant-popup-builder\u0026new=3477334%40instant-popup-builder\u0026sfp_email=\u0026sfph_mail="
},
{
"source": "security@wordfence.com",
"url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8de3d5460?source=cve"
}
],
"sourceIdentifier": "security@wordfence.com",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-862"
}
],
"source": "security@wordfence.com",
"type": "Secondary"
}
]
}
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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