CVE-2026-78576 in Readabler Plugin
Summary
by MITRE • 08/25/2026
The Readabler plugin for WordPress is vulnerable to SQL Injection in all versions up to 2.0.18 (exclusive) due to insufficient escaping on the user supplied parameter and lack of sufficient preparation on the existing SQL query. This makes it possible for unauthenticated attackers to append additional SQL queries into already existing queries that can be used to extract sensitive information from the database.
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Analysis
by VulDB Data Team • 08/25/2026
The Readabler plugin for WordPress, a tool designed to enhance reading experiences by adding features like dark mode and font adjustments, contains a critical security flaw in versions prior to 2.0.18. This vulnerability stems directly from insufficient input validation and sanitization mechanisms within the plugin's codebase. Specifically, user-supplied parameters are not adequately escaped before being incorporated into database queries. In secure software development practices, all data originating from external sources must be treated as untrusted until it has been rigorously validated against expected formats and constraints. The failure to implement these basic safeguards creates a significant attack surface that allows malicious actors to manipulate the intended logic of SQL statements executed by the application backend.
The technical nature of this flaw is classified as an Unrestricted Upload or Injection vulnerability, specifically falling under CWE-89: Improper Neutralization of Special Elements used in an SQL Command, commonly known as SQL Injection. The core issue lies in the lack of prepared statements or parameterized queries when interacting with the WordPress database. Instead of binding variables to precompiled SQL templates, the application concatenates raw user input directly into the query string. This architectural decision enables attackers to inject arbitrary SQL code that is then executed by the database management system alongside legitimate commands. Because this vulnerability exists in a plugin accessible via standard web requests without requiring prior authentication, it represents an unauthenticated attack vector, significantly lowering the barrier for exploitation and increasing the potential scope of impact across vulnerable installations.
The operational impact of exploiting this SQL injection flaw can be severe, ranging from data exfiltration to complete system compromise. An attacker can append additional SQL queries to existing ones to extract sensitive information stored in the WordPress database. This includes user credentials such as hashed passwords, email addresses, and personal identification details associated with registered users. Furthermore, depending on the privileges of the database user account running the web application, an attacker might be able to modify or delete data, alter administrative settings, or potentially execute commands on the underlying operating system through specific database features like xp_cmdshell in Microsoft SQL Server or LOAD_FILE in MySQL. This capability allows for a full chain of compromise where initial access leads to persistent control over the website and its associated infrastructure.
From an offensive security perspective, this vulnerability aligns with techniques documented in the MITRE ATT&CK framework, particularly those related to Collection via Database Query Language Injection and Credential Access through Unsecured Credentials. Attackers typically utilize automated tools or custom scripts to probe for these injection points by manipulating query parameters such as GET requests or POST data payloads containing malicious SQL syntax like single quotes, UNION SELECT statements, or boolean-based blind injections. The success of the attack relies on the database returning error messages that reveal structural details about the schema, which aids in further exploitation steps aimed at extracting specific tables and columns relevant to the attacker's objectives.
Mitigation strategies must address both immediate remediation and long-term security hygiene. The primary and most effective solution is to upgrade the Readabler plugin to version 2.0.18 or later, where these input handling flaws have been corrected by implementing proper parameterized queries and strict type checking for all user inputs. For organizations unable to update immediately due to compatibility constraints, temporary mitigations include deploying a Web Application Firewall configured with rulesets specifically tuned to detect SQL injection patterns in HTTP requests. Additionally, enforcing the principle of least privilege on database accounts ensures that even if an injection occurs, the attacker's ability to perform destructive actions or access unrelated data is restricted. Regular security audits and code reviews focusing on input validation practices are essential to prevent similar vulnerabilities from being introduced into WordPress plugins and themes in the future.