CVE-2026-2831 is an SQL Injection vulnerability identified in the MailArchiver plugin for WordPress, affecting all versions up to and including 4.5.0. The root cause is insufficient escaping and lack of prepared statements for the 'logid' parameter, which is used in SQL queries within the plugin. This improper neutralization of special elements (CWE-89) allows an attacker with Administrator-level access to append arbitrary SQL commands to existing queries. Since the attacker must be authenticated with high privileges, the vulnerability does not allow remote unauthenticated exploitation but enables privilege abuse within compromised or insider accounts. The impact is primarily on confidentiality, as attackers can extract sensitive information from the database, such as user data or configuration details. The vulnerability does not affect data integrity or availability, and no user interaction is required beyond authentication. The CVSS 3.1 score of 4.9 reflects a medium severity, considering the network attack vector, low attack complexity, and high privileges required. No public exploits or patches have been reported at the time of publication, increasing the urgency for organizations to implement mitigations proactively.

The primary impact of CVE-2026-2831 is unauthorized disclosure of sensitive information stored in the WordPress database, which can include user credentials, email archives, and other confidential data managed by the MailArchiver plugin. This can lead to privacy violations, compliance issues, and potential further attacks if sensitive data is leveraged for lateral movement or privilege escalation. Since exploitation requires Administrator-level access, the threat is most significant in environments where user accounts may be compromised or insider threats exist. The vulnerability does not directly impact system availability or data integrity, but the confidentiality breach can undermine trust and lead to reputational damage. Organizations relying on MailArchiver for email archiving within WordPress are at risk, especially if they have weak internal controls or insufficient monitoring of privileged accounts.

To mitigate CVE-2026-2831, organizations should immediately upgrade the MailArchiver plugin to a fixed version once available. In the absence of an official patch, administrators should restrict Administrator-level access strictly to trusted personnel and implement strong multi-factor authentication to reduce the risk of account compromise. Employing Web Application Firewalls (WAFs) with custom rules to detect and block suspicious SQL injection patterns targeting the 'logid' parameter can provide temporary protection. Regularly auditing and monitoring database queries and logs for anomalous activity related to MailArchiver can help detect exploitation attempts early. Additionally, applying the principle of least privilege by limiting plugin usage and database permissions can reduce the potential impact. Finally, organizations should review and harden their WordPress security posture, including timely updates and security plugins that detect privilege abuse.