GHSA-9C7F-G6V7-XWQ7

Vulnerability from github – Published: 2026-03-19 09:30 – Updated: 2026-03-19 09:30
VLAI
Details

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.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
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{
  "affected": [],
  "aliases": [
    "CVE-2026-3475"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-862"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-03-19T08:16:19Z",
    "severity": "MODERATE"
  },
  "details": "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.",
  "id": "GHSA-9c7f-g6v7-xwq7",
  "modified": "2026-03-19T09:30:18Z",
  "published": "2026-03-19T09:30:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-3475"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1761"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/tags/1.1.6/public/class-instant-popup-subscription-public.php#L1772"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1761"
    },
    {
      "type": "WEB",
      "url": "https://plugins.trac.wordpress.org/browser/instant-popup-builder/trunk/public/class-instant-popup-subscription-public.php#L1772"
    },
    {
      "type": "WEB",
      "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="
    },
    {
      "type": "WEB",
      "url": "https://www.wordfence.com/threat-intel/vulnerabilities/id/979962e3-9052-4dc9-94d0-3ec8de3d5460?source=cve"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N",
      "type": "CVSS_V3"
    }
  ]
}


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