{"id":"CVE-2026-109515","revision":"ef00285d9b204d5b9d673c1c7e825093","records":[{"revision":"ef00285d9b204d5b9d673c1c7e825093","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-109515","aliases":[],"title":"MailOptin <= 1.2.78.6 - Unauthenticated Privilege Escalation to 'form_custom_field_mappings' Parameter","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.","state":0,"publishedAt":"2026-10-16T04:27:01.48+00:00","modifiedAt":"2026-10-16T15:09:39.848+00:00","affected":[{"ecosystem":"Vendor product","name":"MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc.","ranges":[],"versions":[],"rawVersionEvidence":"{\n                    \"vendor\": \"properfraction\",\n                    \"product\": \"MailOptin – Popup, Optin Forms & Email Newsletters for Mailchimp, HubSpot, AWeber Etc.\",\n                    \"versions\": [\n                        {\n                            \"version\": \"0\",\n                            \"status\": \"affected\",\n                            \"lessThanOrEqual\": \"1.2.78.6\",\n                            \"versionType\": \"semver\"\n                        }\n                    ],\n                    \"defaultStatus\": \"unaffected\"\n                }"}],"metrics":[{"system":"CVSS 3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8,"severity":"CRITICAL"}],"references":["https://www.wordfence.com/threat-intel/vulnerabilities/id/96111116-6b6f-42fc-98d8-6f5c27dc3c1c?source=cve","https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/connections/WordPressUserRegistrationConnect/Subscription.php#L68","https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/Connections/AbstractConnect.php#L84","https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/AjaxHandler.php#L699","https://plugins.trac.wordpress.org/changeset?reponame=&new=3744644%40mailoptin%2Ftrunk&old=3738326%40mailoptin%2Ftrunk#file4","https://plugins.trac.wordpress.org/changeset/3744644/mailoptin/trunk/src/connections/WordPressUserRegistrationConnect/Subscription.php"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-109515","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-109515","identifiers":["CVE-2026-109515"]},"retained":false,"historicalAffected":[]}],"coverage":[]}