CVE-2026-62138 in Visual Composer Plugin
Summary
by MITRE • 09/11/2026
Contributor Cross Site Scripting (XSS) in Visual Composer Website Builder <= 45.16.1 versions.
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Analysis
by VulDB Data Team • 09/11/2026
The vulnerability identified as Contributor Cross-Site Scripting within the Visual Composer Website Builder plugin for WordPress, affecting versions up to and including 45.16.1, represents a significant security flaw that compromises the integrity of web applications relying on this content management system extension. This specific weakness arises from insufficient input validation and sanitization mechanisms when processing user-supplied data associated with contributor-level accounts. In typical WordPress environments, contributors possess limited privileges compared to administrators or editors, primarily allowing them to write posts but not publish them without approval. However, the flaw in Visual Composer allows these lower-privileged users to inject malicious client-side scripts into pages that are subsequently rendered for other users, thereby bypassing expected access controls and trust boundaries within the application logic.
From a technical perspective, this vulnerability is classified under CWE-79, which denotes Improper Neutralization of Input During Web Page Generation commonly known as Cross-Site Scripting. The root cause lies in the plugin's failure to properly encode or escape special characters such as angle brackets, quotes, and ampersands within user-controlled fields before they are outputted into HTML contexts. When a contributor submits content containing script tags or event handlers like onerror or onload, the Visual Composer engine processes this input without adequate sanitization checks specific to the role-based access control model. Consequently, when an administrator or another authenticated user views the pending post or preview of that content within the WordPress dashboard or frontend interface, the malicious code executes in their browser session under the context of the victim's authentication cookies and privileges.
The operational impact of this vulnerability is severe due to its potential for account takeover and data exfiltration. An attacker with contributor-level access can craft a payload that steals administrative credentials by redirecting users to a phishing site or extracting sensitive information such as CSRF tokens, session IDs, or personal data stored in local storage. Furthermore, because the execution context often involves privileged interfaces like the WordPress admin dashboard when previews are rendered, the impact extends beyond simple defacement. The attacker can manipulate page content, install malicious plugins if they trick an administrator into clicking a crafted link that triggers administrative actions, or redirect traffic to malware distribution sites. This undermines the confidentiality and integrity of the entire web application ecosystem supported by Visual Composer.
In terms of industry frameworks, this vulnerability aligns with MITRE ATT&CK technique T1059, specifically Command and Scripting Interpretation via JavaScript, as well as T1204, User Execution, where the victim is tricked into executing malicious code. The attack vector typically involves social engineering or exploiting public-facing forms to inject payloads that remain dormant until viewed by a privileged user. This highlights the critical importance of validating input not just for technical correctness but also within the context of role-based permissions and output encoding strategies.
To mitigate this vulnerability, immediate action is required from system administrators and developers utilizing Visual Composer Website Builder. The primary remediation step is to upgrade the plugin to version 45.16.2 or later, where the vendor has implemented stricter input sanitization and output escaping mechanisms tailored for contributor-level inputs. Until an update can be applied, temporary mitigations include restricting contributor access if possible, implementing a Web Application Firewall that detects and blocks common XSS payloads in POST requests, and manually reviewing content submitted by contributors before it is rendered or published. Additionally, developers should ensure that all user-generated content undergoes rigorous encoding using context-aware methods such as HTML entity encoding for data inserted into HTML bodies, attribute value escaping for attributes, and JavaScript string escaping when dynamic scripts are involved. Regular security audits and penetration testing focused on role-based access control bypasses can further help identify similar weaknesses in custom implementations or other plugins that interact with Visual Composer's rendering engine.