{"id":"CVE-2026-109515","published":"2026-10-16T05:17:29.597","lastModified":"2026-10-16T15:17:07.900","description":"The MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc. plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 1.2.78.6 This is due to the `subscribe_to_email_list` endpoint accepting an attacker-supplied `optin_data[form_custom_field_mappings]` parameter without any allow-list validation on destination keys, allowing the attacker-controlled mapping to override the administrator's saved mapping and pass arbitrary `wp_users` column names — including `ID` and `user_pass` — directly into `wp_insert_user()` via the `subscribe()` function. This makes it possible for unauthenticated attackers to force `wp_insert_user()` into UPDATE mode on any existing account by supplying a target user's numeric `ID`, overwrite that account's password with a pre-hashed value of their choosing, and thereby take over any WordPress user account — including administrators — leading to full site compromise. Exploitation requires that a WordPress User Registration opt-in form is published somewhere on the site, though the form's UUID is visible in page source and no authentication, nonce, or capability check is required to reach the vulnerable endpoint.","cvssScore":9.8,"cvssSeverity":"CRITICAL","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-269"],"vendors":[],"products":[],"references":[{"url":"https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/connections/WordPressUserRegistrationConnect/Subscription.php#L68","tags":[]},{"url":"https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/AjaxHandler.php#L699","tags":[]},{"url":"https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/Connections/AbstractConnect.php#L84","tags":[]},{"url":"https://plugins.trac.wordpress.org/changeset/3744644/mailoptin/trunk/src/connections/WordPressUserRegistrationConnect/Subscription.php","tags":[]},{"url":"https://plugins.trac.wordpress.org/changeset?reponame=&new=3744644%40mailoptin%2Ftrunk&old=3738326%40mailoptin%2Ftrunk#file4","tags":[]},{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/96111116-6b6f-42fc-98d8-6f5c27dc3c1c?source=cve","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":{"summary":"The MailOptin WordPress plugin has a privilege escalation vulnerability where unauthenticated attackers can manipulate user account details by directly injecting arbitrary database column names into wp_insert_user() function. This allows attackers to overwrite any user's password and take over their account, including administrator accounts.","exploitability":"Exploitation is straightforward requiring only a published registration form with its UUID visible in page source, no authentication or validation required to reach the vulnerable endpoint, making it highly exploitable with minimal effort.","blast_radius":"The vulnerability can lead to complete site compromise as attackers can takeover any WordPress user account including administrators, potentially allowing full control over the entire website and its data.","remediation":"Upgrade to version 1.2.78.7 or later to fix this privilege escalation vulnerability.","detection":"No reliable host or network indicator is derivable from the published description.","tags":["privilege-escalation","wordpress","user-account"],"model":"garnet-coder","analyzedAt":"2026-10-16T08:47:04.403Z"}}