CVE-2019-25148 in WP HTML Mail Plugin
Summary
by MITRE • 06/07/2023
The WP HTML Mail plugin for WordPress is vulnerable to HTML injection in versions up to, and including, 2.9.0.3 due to insufficient input sanitization. This makes it possible for unauthenticated attackers to inject arbitrary HTML in pages that execute if they can successfully trick a administrator into performing an action such as clicking on a link.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 04/09/2026
The WP HTML Mail plugin for WordPress presents a critical HTML injection vulnerability identified as CVE-2019-25148 affecting versions up to and including 2.9.0.3. This vulnerability stems from inadequate input sanitization mechanisms within the plugin's codebase, creating a pathway for malicious actors to inject arbitrary HTML content into affected WordPress installations. The flaw specifically manifests when the plugin processes user-supplied input without proper validation or escaping, allowing attackers to manipulate the HTML output generated by the mail functionality.
The technical nature of this vulnerability places it squarely within CWE-79, which categorizes HTML injection as a form of cross-site scripting that occurs when untrusted data is embedded into web pages without proper sanitization. This weakness enables attackers to execute malicious scripts in the context of the victim's browser, potentially leading to session hijacking, data theft, or further exploitation of the compromised WordPress environment. The vulnerability is particularly concerning because it requires no authentication to exploit, making it accessible to unauthenticated attackers who can leverage social engineering techniques to trick administrators into triggering the malicious payload.
The operational impact of this vulnerability extends beyond simple HTML injection, as it creates opportunities for attackers to perform more sophisticated attacks within the WordPress ecosystem. When administrators inadvertently click on malicious links or interact with compromised content, the injected HTML can execute in their browser context, potentially leading to privilege escalation or lateral movement within the compromised environment. The vulnerability's exploitation requires minimal technical skill, making it attractive to threat actors who can leverage it to compromise WordPress sites and potentially gain unauthorized access to sensitive data or administrative controls.
Mitigation strategies for this vulnerability should focus on immediate remediation through plugin updates to versions that address the input sanitization deficiencies. Administrators should implement comprehensive input validation and output escaping mechanisms to prevent similar vulnerabilities in other components of their WordPress installations. The implementation of web application firewalls and content security policies can provide additional layers of protection by blocking suspicious HTML content and preventing unauthorized script execution. Security monitoring should include regular vulnerability scanning and code review processes to identify similar sanitization issues in other plugins or custom code components. Organizations should also consider implementing user education programs to help administrators recognize and avoid potentially malicious links or content that could trigger such vulnerabilities, aligning with the broader security awareness principles outlined in the MITRE ATT&CK framework for credential access and defense evasion techniques.