{
 "id": "WPSEC-2026-0949",
 "url": "https://wpsec.com/vuln/WPSEC-2026-0949/",
 "json_url": "https://wpsec.com/vuln/WPSEC-2026-0949/advisory.json",
 "markdown_url": "https://wpsec.com/vuln/WPSEC-2026-0949/index.md",
 "title": "MailPoet – Newsletters, Email Marketing, and Automation <= 5.41.0 - Unauthenticated Open Redirect via 'referrer_form_url' Parameter",
 "description": "The MailPoet plugin for WordPress is vulnerable to Open Redirect via the 'referrer_form_url' parameter of the CAPTCHA page shown for WordPress and WooCommerce registration forms in all versions up to, and including, 5.41.0, due to the CAPTCHA page using the request-supplied 'referrer_form_url' value as the form's submission target without validating its host, and rendering every other request value as a hidden form field. This makes it possible for unauthenticated attackers to craft a link to the site's CAPTCHA page whose form sends the visitor, and the data the form submits, to an attacker-controlled external site when the visitor submits the CAPTCHA.",
 "plugin": {
  "slug": "mailpoet",
  "name": "MailPoet – Newsletters, Email Marketing, and Automation",
  "full_name": "MailPoet – Newsletters, Email Marketing, and Automation",
  "wordpress_org": "https://wordpress.org/plugins/mailpoet/",
  "advisories_url": "https://wpsec.com/vuln/plugin/mailpoet/",
  "attacksurface": "https://attacksurface.wpsec.com/plugin/mailpoet"
 },
 "type": "REDIRECT",
 "cwe": [
  "CWE-601"
 ],
 "cve": [],
 "cvss": {
  "version": "3.1",
  "score": 6.1,
  "vector": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N",
  "severity": "Medium"
 },
 "affected": {
  "ranges": [
   {
    "from": null,
    "from_inclusive": true,
    "to": "5.42.0",
    "to_inclusive": false
   }
  ],
  "text": [
   "all versions before 5.42.0"
  ]
 },
 "introduced_in": null,
 "fixed_in": "5.42.0",
 "remediation": "Update to 5.42.0 or later.",
 "fix_released": "2026-10-13T14:24:47+00:00",
 "published": "2026-10-14T14:57:06+00:00",
 "updated": "2026-10-14T12:18:11.887584+00:00",
 "also_published_as": null,
 "references": [
  "https://wpsec.com/vuln/WPSEC-2026-0949/",
  "https://plugins.svn.wordpress.org/mailpoet/tags/5.42.0/",
  "https://wordpress.org/plugins/mailpoet/"
 ],
 "attacksurface_url": "https://attacksurface.wpsec.com/plugin/mailpoet",
 "source": "WPSec",
 "license": {
  "name": "CC BY 4.0",
  "url": "https://creativecommons.org/licenses/by/4.0/"
 },
 "usage": {
  "plugin": "Medium",
  "affected_versions": "Medium",
  "as_of": "2026-10-14"
 }
}