CVE-2020-25286 in WordPress
Summary
by MITRE
In wp-includes/comment-template.php in WordPress before 5.4.2, comments from a post or page could sometimes be seen in the latest comments even if the post or page was not public.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 09/14/2020
This vulnerability exists within the WordPress content management system's comment handling mechanism, specifically in the comment-template.php file that governs how comments are displayed on websites. The flaw represents a critical access control issue that allows unauthorized users to view comments associated with private or non-public content, effectively bypassing the intended security restrictions that should prevent such disclosure. The vulnerability affects WordPress versions prior to 5.4.2, indicating that this was a persistent issue within the platform's core functionality that required a specific patch to address. This type of information disclosure vulnerability falls under the category of improper access control as defined by CWE-284, where the system fails to properly enforce access restrictions on sensitive data. The issue stems from the comment template system not adequately validating whether the parent post or page containing the comments is accessible to the current user, creating a scenario where comment visibility is not properly tied to content visibility permissions.
The technical implementation of this vulnerability occurs when WordPress processes comment display functions that aggregate comments from various sources into a latest comments feed or widget. The system fails to perform proper access checks on the parent content before displaying associated comments, allowing comments from private posts or pages to appear in publicly accessible comment sections. This flaw can be exploited by attackers who do not have direct access to the private content but can observe the comment aggregation system, effectively creating a data leakage mechanism. The vulnerability operates at the application layer and requires no special privileges to exploit, making it particularly dangerous as it can be leveraged by any visitor to the website. The root cause lies in the lack of proper content access validation within the comment display logic, where the system assumes that if comments exist, they should be visible regardless of the parent content's access restrictions.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can lead to the exposure of sensitive conversations, personal information, or internal discussions that were intended to remain private within specific user groups or content sections. Attackers could potentially gather intelligence about website administrators, users, or business operations by accessing comments from private posts, which might contain confidential information or reveal user behavior patterns. The vulnerability affects all WordPress installations running versions before 5.4.2, making it a widespread concern across numerous websites that may not have been regularly updated or patched. This type of vulnerability can be categorized under the ATT&CK technique T1213.002 for data from information repositories, where adversaries extract sensitive data through access to comment systems or similar aggregated data sources. The exposure of private comments could also impact user privacy and trust in the platform, potentially leading to compliance violations in environments where data protection regulations apply.
Mitigation strategies for this vulnerability require immediate patching of WordPress installations to version 5.4.2 or later, which contains the necessary fixes to properly enforce access controls on comment display. System administrators should also implement monitoring for unusual comment access patterns and consider additional security measures such as restricting comment visibility settings or implementing more granular access controls for comment systems. Organizations should conduct regular security assessments of their WordPress installations to identify and remediate similar access control vulnerabilities. The fix implemented in WordPress 5.4.2 addresses the core issue by ensuring that comment display functions properly validate the accessibility of parent content before rendering associated comments, preventing the leakage of private comment data. This remediation aligns with security best practices for maintaining proper access control boundaries within web applications and demonstrates the importance of regular security updates in protecting against information disclosure vulnerabilities.