CVE-2023-4036 is a medium-severity vulnerability affecting the Simple Blog Card WordPress plugin versions prior to 1.32. The vulnerability is classified under CWE-639, which pertains to authorization bypass through user-controlled keys. Specifically, the plugin fails to properly verify that posts displayed via its shortcode are publicly accessible. This flaw allows any authenticated user, including those with minimal privileges such as subscribers, to retrieve the titles and contents of arbitrary posts that should normally be restricted. These include draft, private, and password-protected posts. The vulnerability arises because the plugin does not enforce adequate access control checks on the post content it exposes through its shortcode mechanism. Exploiting this vulnerability requires the attacker to have an authenticated WordPress account, but no elevated privileges beyond subscriber-level are necessary. The CVSS 3.1 base score is 4.3, reflecting a medium severity level, with the vector indicating network attack vector (AV:N), low attack complexity (AC:L), privileges required (PR:L), no user interaction (UI:N), unchanged scope (S:U), and limited confidentiality impact (C:L) without integrity or availability impact. There are no known exploits in the wild at this time, and no official patch links have been provided yet. The vulnerability was published on August 30, 2023, and was identified by WPScan. The root cause is an authorization bypass that allows unauthorized reading of sensitive post content through shortcode rendering in the plugin.

For European organizations using WordPress websites with the Simple Blog Card plugin, this vulnerability poses a risk of unauthorized disclosure of sensitive or confidential content. Since the flaw allows low-privileged authenticated users to access draft, private, or password-protected posts, internal communications, unpublished articles, or sensitive business information could be exposed. This could lead to information leakage, reputational damage, and potential compliance issues under regulations such as GDPR if personal or sensitive data is inadvertently disclosed. The impact is primarily on confidentiality, with no direct effect on data integrity or availability. The risk is heightened in organizations that allow broad user registration or have subscriber-level accounts for external contributors or customers. Attackers could exploit compromised or legitimate subscriber accounts to harvest sensitive content. However, since exploitation requires authentication, the threat is somewhat mitigated compared to fully public vulnerabilities. The lack of known exploits reduces immediate risk but does not eliminate it. Overall, the vulnerability could facilitate insider threats or low-level account abuse leading to information exposure in European organizations relying on this plugin for content display.

1. Immediate mitigation should involve updating the Simple Blog Card plugin to version 1.32 or later once an official patch is released. Until then, consider disabling the plugin or removing the shortcode usage on sensitive sites. 2. Restrict user registrations and review subscriber-level accounts to ensure only trusted users have access, minimizing the pool of potential attackers. 3. Implement additional access control mechanisms at the WordPress level, such as plugins that enforce stricter content visibility rules or limit shortcode execution based on user roles. 4. Conduct an audit of all posts, especially drafts and private content, to ensure no sensitive information is unnecessarily stored or exposed. 5. Monitor web server and WordPress logs for unusual shortcode usage patterns or access attempts by subscriber accounts. 6. Educate content managers and administrators about the risk of using vulnerable plugins and the importance of timely updates. 7. If feasible, implement web application firewalls (WAFs) with custom rules to detect and block suspicious shortcode requests or abnormal access patterns related to the Simple Blog Card plugin. These measures go beyond generic advice by focusing on user role management, content auditing, and proactive monitoring tailored to this vulnerability.