CVE-2024-49593 in Advanced Custom Fields Plugin
Summary
by MITRE • 10/17/2024
In Advanced Custom Fields (ACF) before 6.3.9 and Secure Custom Fields before 6.3.6.3 (plugins for WordPress), using the Field Group editor to edit one of the plugin's fields can result in execution of a stored XSS payload. NOTE: if you wish to use the WP Engine alternative update mechanism for the free version of ACF, then you can follow the process shown at the advancedcustomfields.com blog URL within the References section below.
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Analysis
by VulDB Data Team • 03/04/2025
The vulnerability identified as CVE-2024-49593 affects the Advanced Custom Fields (ACF) and Secure Custom Fields WordPress plugins, which are widely used for creating custom fields and content management interfaces. This security flaw exists in versions prior to 6.3.9 for ACF and 6.3.6.3 for Secure Custom Fields, representing a critical threat to WordPress site security. The vulnerability stems from insufficient input validation and output escaping within the Field Group editor functionality, creating a pathway for malicious actors to inject persistent cross-site scripting payloads that can execute in the context of authenticated users' browsers.
The technical implementation of this vulnerability occurs when administrators or users with sufficient privileges utilize the Field Group editor to modify plugin fields. The flaw resides in how the plugin processes and renders user-supplied data within the administrative interface, failing to properly sanitize or escape potentially malicious input before storing it in the database. When other users with appropriate permissions access the affected fields, the stored XSS payload executes in their browser context, potentially allowing attackers to perform actions on their behalf, steal session cookies, or redirect them to malicious sites. This vulnerability is categorized under CWE-79 as Cross-Site Scripting, specifically representing a stored XSS variant where malicious code is permanently stored on the server and executed when users access affected pages.
The operational impact of CVE-2024-49593 extends beyond simple data theft, as it can enable attackers to establish persistent footholds within WordPress environments. An attacker who successfully exploits this vulnerability can leverage the stored XSS to perform privilege escalation attacks, modify content, steal administrator credentials, or even deploy additional malware through the compromised user sessions. The vulnerability is particularly dangerous in multi-user environments where administrators frequently use the ACF Field Group editor, as the attack surface expands with each user interaction. This weakness aligns with ATT&CK technique T1566.001 for initial access through malicious content, and T1071.001 for application layer protocol usage, as the attack vector involves manipulating web application interfaces and executing code through browser-based attacks.
Mitigation strategies for this vulnerability require immediate patching of affected versions to the latest releases, which include proper input sanitization and output escaping mechanisms. System administrators should implement additional security measures such as restricting access to the Field Group editor for non-essential users, implementing content security policies, and monitoring for unusual administrative activities. The WordPress security community recommends enabling two-factor authentication, maintaining regular backups, and using security plugins that can detect and block malicious script injections. Organizations should also conduct comprehensive security audits of their WordPress installations to identify other potential vulnerabilities, as this flaw may indicate broader security weaknesses in the site's configuration or user privilege management. The vulnerability demonstrates the critical importance of input validation in web applications, particularly in content management systems where administrators frequently interact with rich text editors and custom field configurations.