CVE-2025-4579 in WP Content Security Plugin Plugin
Summary
by MITRE • 05/15/2025
The WP Content Security Plugin plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the blocked-uri and effective-directive parameters in all versions up to, and including, 2.3 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 05/15/2025
The WP Content Security Plugin for WordPress represents a critical security vulnerability classified as CVE-2025-4579, affecting all versions up to and including 2.3. This vulnerability manifests as a stored cross-site scripting flaw that exploits insufficient input sanitization and output escaping mechanisms within the plugin's handling of specific parameters. The affected parameters include blocked-uri and effective-directive, which when improperly processed create persistent injection points that can be exploited by unauthenticated attackers to execute malicious scripts within the context of victim browsers.
The technical exploitation of this vulnerability occurs through the manipulation of HTTP headers that the plugin processes to enforce content security policies. When the plugin fails to properly sanitize user-supplied input from the blocked-uri and effective-directive parameters, it allows attackers to inject malicious JavaScript code that gets stored within the plugin's processing mechanisms. This stored payload becomes persistent and executes whenever legitimate users access pages that trigger the vulnerable code path, creating a server-side injection scenario that violates fundamental web security principles.
The operational impact of this vulnerability extends beyond simple script execution, as it enables attackers to perform a wide range of malicious activities including session hijacking, credential theft, data exfiltration, and privilege escalation within the WordPress environment. The vulnerability's unauthenticated nature makes it particularly dangerous as attackers can exploit it without requiring valid credentials or administrative access. This weakness directly violates the principle of least privilege and undermines the security model of the WordPress platform, potentially allowing attackers to compromise entire websites and their associated user data.
The vulnerability aligns with CWE-79 (Cross-Site Scripting) and demonstrates characteristics consistent with ATT&CK technique T1566 (Phishing) and T1059 (Command and Scripting Interpreter) through the execution of malicious scripts in user browsers. Organizations running vulnerable versions of this plugin face significant risk of data breaches and system compromise, as the stored nature of the XSS vulnerability means that once exploited, malicious payloads persist until the plugin is updated or the affected parameters are cleared from the system's memory. The vulnerability's persistence makes it particularly challenging to detect and remediate without comprehensive system scanning and patch management protocols.
Mitigation strategies should prioritize immediate patching of the WP Content Security Plugin to versions that address the input sanitization and output escaping deficiencies. System administrators should implement additional security layers including web application firewalls, content security policy headers, and regular security scanning to identify potential exploitation attempts. The vulnerability highlights the importance of proper input validation and output encoding practices as outlined in OWASP Top Ten and NIST cybersecurity frameworks, emphasizing that all user-supplied data must be rigorously validated before processing and properly escaped before output to prevent malicious code execution. Organizations should also conduct thorough security audits of their WordPress installations to identify similar vulnerabilities in other plugins and themes that may be susceptible to similar input handling flaws.