---
title: "MailOptin WordPress Plugin - Privilege Escalation"
description: "MailOptin WordPress plugin <= 1.2.78.6 contains a privilege escalation caused by lack of allow-list validation on optin_data[form_custom_field_mappings] in subscribe_to_email_list endpoint, letting unauthenticated attackers overwrite any user password and take over accounts, exploit requires a published WordPress User Registration opt-in form."
url: https://panop.io/threat-heartbeat/CVE-2026-109515/
---

# CVE-2026-109515 MailOptin WordPress Plugin - Privilege Escalation

MailOptin WordPress plugin <= 1.2.78.6 contains a privilege escalation caused by lack of allow-list validation on optin\_data\[form\_custom\_field\_mappings\] in subscribe\_to\_email\_list endpoint, letting unauthenticated attackers overwrite any user password and take over accounts, exploit requires a published WordPress User Registration opt-in form.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-109515)

## Details

Type

Broken Access Control

Impact

Privilege Escalation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Published

16 October 2026

Updated

16 October 2026

Weakness

[CWE-269](https://cwe.mitre.org/data/definitions/269.html)

## Vendor fix

Update to the latest version beyond 1.2.78.6.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-109515](https://nvd.nist.gov/vuln/detail/CVE-2026-109515)
- [https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/AjaxHandler.php#L699](https://plugins.trac.wordpress.org/browser/mailoptin/tags/1.2.78.5/src/core/src/AjaxHandler.php#L699)
- [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/Connections/AbstractConnect.php#L84)
- [https://plugins.trac.wordpress.org/changeset/3744644/mailoptin/trunk/src/connections/WordPressUserRegistrationConnect/Subscription.php](https://plugins.trac.wordpress.org/changeset/3744644/mailoptin/trunk/src/connections/WordPressUserRegistrationConnect/Subscription.php)
- [https://plugins.trac.wordpress.org/changeset?reponame=&new=3744644%40mailoptin%2Ftrunk&old=3738326%40mailoptin%2Ftrunk#file4](https://plugins.trac.wordpress.org/changeset?reponame=&new=3744644%40mailoptin%2Ftrunk&old=3738326%40mailoptin%2Ftrunk#file4)
- [https://www.wordfence.com/threat-intel/vulnerabilities/id/96111116-6b6f-42fc-98d8-6f5c27dc3c1c?source=cve](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/connections/WordPressUserRegistrationConnect/Subscription.php#L68)

[← All CVEs](https://panop.io/threat-heartbeat/)

## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

[Book a demo](https://panop.io/demo)