CVE-2026-1608 in Video Onclick Plugin
Summary
by MITRE • 02/07/2026
The Video Onclick plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the plugin's `youtube` shortcode in all versions up to, and including, 0.4.7 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 • 02/08/2026
The Video Onclick plugin for WordPress presents a critical stored cross-site scripting vulnerability identified as CVE-2026-1608 affecting versions through 0.4.7. This vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's youtube shortcode implementation, creating a persistent security flaw that can be exploited by authenticated attackers. The vulnerability specifically targets the plugin's handling of user-supplied attributes, allowing malicious code injection that persists in the system until manually removed. The attack vector requires an authenticated user with contributor-level privileges or higher, making it particularly concerning as it can be leveraged by users who should have limited administrative capabilities.
The technical flaw manifests in the plugin's insufficient validation of input parameters passed to the youtube shortcode functionality. When users with appropriate permissions create or modify content containing malicious payloads within the plugin's attributes, these inputs are not properly sanitized before being stored in the database. The vulnerability operates under CWE-79 which classifies the issue as a failure to sanitize input, allowing attackers to inject malicious scripts that will execute whenever legitimate users view pages containing the compromised content. This stored XSS vulnerability creates a persistent threat that can affect any user who accesses pages where the malicious content has been injected, regardless of their privilege level.
The operational impact of this vulnerability extends beyond simple script execution as it can enable attackers to perform various malicious activities including session hijacking, credential theft, and redirection to malicious sites. Since the vulnerability affects authenticated users with contributor access or higher, it provides attackers with a foothold to escalate privileges or compromise other users within the WordPress environment. The persistent nature of stored XSS means that once the malicious payload is injected, it remains active until manually removed, potentially affecting numerous users over extended periods. This vulnerability also aligns with ATT&CK technique T1546.001 which involves the use of malicious scripts to establish persistence and maintain access within compromised systems.
Mitigation strategies for CVE-2026-1608 should prioritize immediate plugin updates to versions that address the sanitization and escaping issues. Administrators must implement strict input validation measures and ensure proper output escaping for all user-supplied data within the plugin's shortcode functionality. Regular security audits of WordPress plugins should include verification of input sanitization practices and output escaping mechanisms to prevent similar vulnerabilities. Additionally, implementing role-based access controls and monitoring user activities can help detect unauthorized modifications to content that might indicate exploitation attempts. The vulnerability serves as a reminder of the importance of proper security practices in plugin development, particularly concerning the handling of user inputs and the implementation of robust sanitization and escaping mechanisms to protect against cross-site scripting attacks.