CVE-2023-5314 in WP Extra Plugin
Summary
by MITRE • 11/22/2023
The WP EXtra plugin for WordPress is vulnerable to unauthorized access to restricted functionality due to a missing capability check on the 'test-email' section of the register() function in versions up to, and including, 6.2. This makes it possible for authenticated attackers, with minimal permissions such as a subscriber, to send emails with arbitrary content to arbitrary locations from the affected site's mail server.
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Analysis
by VulDB Data Team • 04/11/2026
The WP EXtra plugin vulnerability CVE-2023-5314 represents a critical authorization flaw that undermines the security model of WordPress installations. This vulnerability exists within the plugin's register() function where the 'test-email' section fails to implement proper capability validation. The flaw allows attackers who have already gained access to a low-privilege account such as a subscriber to bypass normal access controls and execute unauthorized email sending operations. This represents a significant escalation of privileges vulnerability that directly violates the principle of least privilege fundamental to secure system design.
The technical implementation of this vulnerability stems from the absence of capability checks within the plugin's codebase. According to CWE-284, this constitutes an improper access control issue where the application fails to properly verify user permissions before executing sensitive operations. The missing capability check means that any authenticated user regardless of their role can access the test-email functionality, which should typically be restricted to administrators or users with specific privileges. This flaw specifically affects versions up to and including 6.2 of the WP EXtra plugin, indicating that the vulnerability has existed for multiple releases and likely went unnoticed due to insufficient security review processes during development.
The operational impact of this vulnerability extends beyond simple unauthorized email sending capabilities. Attackers can leverage this flaw to conduct phishing campaigns, spam distribution, or even attempt to exploit the mail server for further attacks. The ability to send emails with arbitrary content from the compromised site's mail server creates a vector for social engineering attacks that can appear legitimate to recipients. This vulnerability also potentially enables attackers to use the compromised mail server for spamming activities, which could lead to the affected domain being blacklisted by email providers. The implications are particularly severe in enterprise environments where the compromised WordPress site might be used as a platform for malicious communications, making this a significant concern for organizations relying on WordPress for their web presence.
Mitigation strategies for this vulnerability should focus on immediate remediation through plugin updates to versions that include proper capability checks. Organizations should also implement network-level restrictions on outbound email traffic to limit the potential damage from compromised accounts. According to ATT&CK framework, this vulnerability could be categorized under T1190 - Exploit Public-Facing Application, where attackers use misconfigured applications to gain unauthorized access. Security teams should also consider implementing monitoring for unusual email sending patterns and establishing privileged access management controls to prevent unauthorized users from gaining access to email functionality. Regular security audits of WordPress plugins and themes remain essential to identify similar authorization flaws that could compromise system integrity.