CVE-2026-102562: AcyMailing <= 11.1.0 - Unauthenticated Stored Cross-Site Scripting via 'customField[]' Parameter
The AcyMailing plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the customField[] parameter of the public frontusers::subscribe endpoint in versions up to, and including, 11.1.0. This is due to insufficient input sanitization and output escaping in the acymcleanVar() sanitizer, whose HTML-tag stripper only matches complete tags (requiring a closing '>'), together with SubscriberInsertion::replaceUserInformation() and the archive view template, which substitute the stored subscriber field value into the mail body and emit it without HTML encoding. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses the online-archive URL for the poisoned subscriber, including administrators who click the plugin-generated link in the Subscribers → History screen.
Affected Software
Event History
Frequently Asked Questions
Does exploitation require an attacker account or user interaction?
No attacker authentication is required. An attacker can submit a crafted value through the public frontusers::subscribe endpoint using the customField[] parameter.
When does the injected script execute, and who may be affected?
The script executes when someone accesses the online-archive URL associated with the poisoned subscriber. This can include administrators who open the plugin-generated link from the Subscribers → History screen.