CVE-2025-12028 is a Cross-Site Request Forgery (CSRF) vulnerability identified in the IndieAuth plugin for WordPress, affecting all versions up to and including 4.5.4. The vulnerability stems from the absence of nonce verification in the login_form_indieauth() function and the authorization endpoint located at wp-login.php?action=indieauth. Nonce tokens are critical for preventing CSRF attacks by ensuring that requests are intentionally made by authenticated users. Without this protection, an attacker can craft malicious requests that, when executed by an authenticated user (e.g., by clicking a link or visiting a malicious website), cause the user’s browser to unknowingly approve OAuth authorization requests for attacker-controlled applications. This approval grants the attacker an authorization code, which can then be exchanged for an access token with scopes that allow creating, updating, or deleting content on behalf of the victim. The attack does not require the attacker to be authenticated or have elevated privileges, but it does require user interaction. The vulnerability has a CVSS 3.1 base score of 8.8, reflecting its high impact on confidentiality, integrity, and availability. Although no active exploits have been reported, the vulnerability poses a significant risk to WordPress sites using IndieAuth, particularly those that rely on OAuth for authentication and authorization. The lack of nonce verification is a fundamental security oversight that enables attackers to bypass standard CSRF protections. Given the widespread use of WordPress in Europe and the popularity of IndieAuth for decentralized authentication, this vulnerability could be leveraged to compromise user accounts, leading to unauthorized content manipulation or data breaches.

For European organizations, the impact of CVE-2025-12028 can be substantial. Many European businesses, media outlets, and governmental agencies use WordPress as their content management system, often integrating IndieAuth for decentralized authentication. Successful exploitation allows attackers to hijack user accounts with permissions to create, update, or delete content, potentially leading to defacement, misinformation campaigns, data loss, or unauthorized data disclosure. This can damage organizational reputation, violate data protection regulations such as GDPR, and disrupt business operations. The attack vector requires user interaction, which means phishing or social engineering campaigns could be effective, especially against less security-aware users. Organizations with high-value or sensitive content, such as news agencies, public institutions, or e-commerce platforms, are at greater risk. Additionally, compromised accounts could be used as a foothold for further lateral movement or to distribute malware. The absence of known exploits in the wild provides a window for proactive mitigation, but the high CVSS score underscores the urgency of addressing this vulnerability.

To mitigate CVE-2025-12028, European organizations should take the following specific actions: 1) Immediately audit all WordPress installations for the presence of the IndieAuth plugin and identify versions up to 4.5.4. 2) Apply patches or updates from the IndieAuth maintainers as soon as they become available; if no official patch exists, consider disabling the plugin temporarily to eliminate the attack surface. 3) Implement nonce verification in the login_form_indieauth() function and the authorization endpoint to ensure that all OAuth authorization requests are validated against CSRF. 4) Enhance user awareness through targeted training to recognize phishing attempts and avoid clicking suspicious links, especially when logged into WordPress sites. 5) Employ web application firewalls (WAFs) with custom rules to detect and block suspicious requests targeting the vulnerable endpoints. 6) Monitor logs for unusual OAuth authorization activities or unexpected token exchanges. 7) Restrict OAuth scopes to the minimum necessary to limit potential damage if an account is compromised. 8) Consider multi-factor authentication (MFA) for WordPress accounts to add an additional layer of security, although this may not fully prevent CSRF attacks, it can reduce overall risk. 9) Regularly review and update security policies to incorporate lessons learned from this vulnerability and improve incident response capabilities.