CVE-2017-14726 in WordPress
Summary
by MITRE
Before version 4.8.2, WordPress was vulnerable to a cross-site scripting attack via shortcodes in the TinyMCE visual editor.
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Analysis
by VulDB Data Team • 01/14/2021
The vulnerability identified as CVE-2017-14726 represents a critical cross-site scripting flaw affecting WordPress versions prior to 4.8.2. This security weakness was discovered within the TinyMCE visual editor component that WordPress utilizes for content creation and editing. The vulnerability specifically exploited the handling of shortcodes within the visual editor interface, creating a pathway for malicious actors to inject harmful scripts into the WordPress administrative environment. The flaw existed in the sanitization and processing mechanisms that govern how shortcode attributes and content are rendered within the rich text editor, allowing attackers to bypass standard input validation measures.
The technical exploitation of this vulnerability occurs when an authenticated attacker with access to the WordPress admin interface can create or modify posts and pages containing maliciously crafted shortcodes. These shortcodes, when processed by the vulnerable TinyMCE editor, would execute unintended JavaScript code in the context of the administrator's browser session. This particular flaw falls under the CWE-79 category of Cross-Site Scripting, specifically representing a stored XSS vulnerability since the malicious code persists in the content and executes whenever the affected page is viewed by a user with sufficient privileges. The vulnerability demonstrates a failure in proper output encoding and input sanitization within the WordPress content management system's rich text editing capabilities.
The operational impact of CVE-2017-14726 extends beyond simple script execution, as it provides attackers with the potential to hijack administrator sessions, steal sensitive cookies, perform unauthorized actions on behalf of users, and ultimately gain full control over compromised WordPress installations. Attackers could leverage this vulnerability to inject malicious payloads that would execute in the context of privileged users, potentially leading to complete system compromise. The risk is particularly elevated because the vulnerability affects the administrative interface where users have the highest level of access and permissions within the WordPress environment. This flaw aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, and T1546.001 for Event Triggered Execution, as it enables persistent malicious code execution through the editor interface. The vulnerability also demonstrates a lack of proper privilege separation and input validation that could be exploited for privilege escalation attacks.
Mitigation strategies for CVE-2017-14726 primarily focus on immediate remediation through WordPress version updates to 4.8.2 or later, which contain the necessary patches to address the shortcode sanitization issues. Organizations should also implement additional security measures including regular security audits of the WordPress installation, monitoring of admin interface activities, and implementation of web application firewalls to detect and block malicious payload attempts. The patch released by WordPress addressed the core issue by improving the sanitization of shortcode attributes and content processing within the TinyMCE editor, ensuring that user-supplied input is properly escaped and validated before being rendered in the visual interface. Security administrators should also consider implementing content security policies, restricting administrative access to trusted networks, and maintaining regular backups to ensure rapid recovery in case of successful exploitation attempts. The vulnerability underscores the importance of keeping content management systems updated and highlights the critical need for robust input validation and output encoding mechanisms in web applications.