CVE-2021-38312 is a high-severity vulnerability affecting the Gutenberg Template Library & Redux Framework plugin for WordPress, specifically versions up to and including 4.2.11. The core issue lies in an incorrect authorization check within the REST API endpoints registered under the “redux/v1/templates/” REST route, implemented in the file “redux-templates/classes/class-api.php”. The permissions_callback function responsible for authorizing access to these endpoints only verifies if the user has the 'edit_posts' capability. In WordPress, this capability is granted not only to administrators but also to lower-privileged roles such as contributors. This flawed authorization allows users with contributor-level access to perform actions beyond their intended permissions, including installing arbitrary plugins from the WordPress repository and editing arbitrary posts. The vulnerability is classified under CWE-863 (Incorrect Authorization) and CWE-280 (Improper Access Control). The CVSS v3.1 base score is 7.1, indicating a high severity level, with the vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:L. This means the vulnerability can be exploited remotely over the network with low attack complexity, requires low privileges (contributor-level), no user interaction, and impacts integrity and availability but not confidentiality. Although no known exploits are reported in the wild, the potential for privilege escalation and unauthorized plugin installation poses a significant risk to WordPress sites using the affected plugin versions. Attackers could leverage this vulnerability to inject malicious code, backdoors, or disrupt site functionality.

For European organizations relying on WordPress websites that utilize the Gutenberg Template Library & Redux Framework plugin, this vulnerability presents a substantial risk. Unauthorized plugin installation can lead to the deployment of malicious plugins that compromise site integrity, steal sensitive data, or create persistent backdoors. The ability for lower-privileged users to escalate their capabilities undermines internal security policies and can facilitate insider threats or exploitation by compromised contributor accounts. This could result in website defacement, data breaches, service disruptions, and reputational damage. Given the widespread use of WordPress across European businesses, including e-commerce, media, and public sector websites, the impact could be broad. Additionally, compromised sites may be used as launchpads for further attacks, including phishing or malware distribution, affecting customers and partners. The vulnerability also raises compliance concerns under GDPR if personal data is exposed or integrity is compromised.

To mitigate this vulnerability, European organizations should immediately update the Gutenberg Template Library & Redux Framework plugin to a version later than 4.2.11 where the authorization checks have been corrected. If an update is not immediately available, organizations should restrict contributor-level access or disable the affected REST API endpoints via custom code or security plugins that allow fine-grained REST API control. Implementing a Web Application Firewall (WAF) with rules targeting suspicious REST API calls can help detect and block exploitation attempts. Regularly auditing user roles and permissions to ensure that only trusted users have contributor or higher privileges is critical. Additionally, monitoring plugin installations and changes to the WordPress environment can provide early detection of unauthorized activity. Organizations should also consider employing security plugins that enforce stricter access controls and logging. Finally, maintaining regular backups and having an incident response plan will help recover quickly if exploitation occurs.