CVE-2024-2026 in Passster Plugin
Summary
by MITRE • 04/10/2024
The Passster plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's content_protector shortcode in all versions up to, and including, 4.2.6.4 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers, with contributor-level access and above, 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 • 04/14/2026
The Passster plugin for WordPress presents a significant security vulnerability classified as CVE-2024-2026, which manifests as a stored cross-site scripting flaw within the plugin's content_protector shortcode functionality. This vulnerability affects all versions through 4.2.6.4 and represents a critical threat to WordPress installations that rely on this plugin for content protection. The flaw exists in the plugin's handling of user-supplied attributes within the shortcode implementation, where insufficient input sanitization and output escaping mechanisms fail to properly validate or encode malicious content submitted by attackers.
The technical nature of this vulnerability stems from the plugin's failure to adequately sanitize user input parameters passed to the content_protector shortcode. When authenticated users with contributor-level access or higher submit content containing malicious scripts through the plugin's interface, these scripts are stored within the WordPress database and subsequently executed whenever legitimate users access pages containing the compromised shortcode. This represents a classic stored XSS attack vector where the malicious payload persists in the application's data store rather than being reflected in a single HTTP request. The vulnerability operates under CWE-79 which specifically addresses Cross-Site Scripting flaws, and aligns with ATT&CK technique T1566.001 for Initial Access through Spearphishing Attachments, as attackers can leverage this vulnerability to deliver malicious payloads to end users.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with a persistent foothold within the WordPress environment. Contributors and above typically have sufficient privileges to modify content and create pages, making them ideal targets for exploitation. Once a malicious script is injected, it can perform various malicious activities including stealing user session cookies, redirecting users to malicious sites, defacing content, or even executing additional attacks through the victim's browser context. The vulnerability's persistence means that the malicious code will execute automatically for any user who accesses the affected pages, making it particularly dangerous for high-traffic websites where the attack surface is broad and the potential for widespread impact is significant.
Mitigation strategies for this vulnerability require immediate attention from WordPress administrators and security teams. The primary recommendation involves upgrading to the latest version of the Passster plugin where the XSS vulnerability has been addressed through proper input sanitization and output escaping mechanisms. Organizations should also implement additional defensive measures including role-based access control reviews to limit contributor privileges where possible, regular security audits of installed plugins, and monitoring for unauthorized content modifications. Security professionals should consider implementing content security policies to limit script execution capabilities and establish automated scanning procedures to detect similar vulnerabilities in other plugins. The vulnerability highlights the importance of proper input validation and output encoding practices as outlined in the OWASP Top 10 security standards, and demonstrates how seemingly minor implementation flaws can create substantial security risks in content management systems.