CVE-2026-18988 in Easy Accordion Plugin
Summary
by MITRE • 08/08/2026
The Easy Accordion plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'accordionTitleTag' block attribute in versions up to, and including, 3.1.8. This is due to insufficient input sanitization and output escaping in the accordion_header_renderer() function, which emits the attacker-supplied tag name using esc_attr() in an HTML tag-name context instead of tag_escape(). 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 • 08/08/2026
The Easy Accordion plugin for WordPress presents a significant security vulnerability classified as stored cross-site scripting that affects versions up to and including 3.1.8. This flaw resides within the accordion_header_renderer() function where the plugin fails to properly sanitize user-supplied input for the 'accordionTitleTag' block attribute. The vulnerability occurs because the plugin employs esc_attr() function in an HTML tag-name context rather than utilizing the more appropriate tag_escape() function, creating a pathway for malicious code injection that can persist across multiple page views.
The technical implementation of this vulnerability stems from inadequate input validation and output escaping mechanisms within the plugin's rendering process. When an attacker with contributor-level privileges or higher submits malicious content through the accordionTitleTag parameter, the insufficient sanitization allows crafted script tags to be stored within the WordPress database. This stored content then executes whenever any user accesses pages containing the vulnerable accordion blocks, making it a persistent threat that can affect multiple users over time. The vulnerability specifically exploits the difference between esc_attr() which is designed for attribute values and tag_escape() which properly handles HTML tag names, demonstrating a fundamental misunderstanding of WordPress security best practices.
The operational impact of this vulnerability extends beyond simple script execution as it provides attackers with a means to perform various malicious activities including session hijacking, credential theft, and redirection to malicious sites. Since the vulnerability requires only contributor-level access, it represents a significant risk for WordPress installations where multiple users have editing privileges or where contributor accounts may be compromised. The stored nature of the XSS attack means that the malicious code remains active even after the initial injection, potentially affecting all users who view pages containing the vulnerable accordion elements until the plugin is updated or the malicious content is manually removed.
Organizations should immediately update to the latest version of the Easy Accordion plugin where this vulnerability has been patched, as no remediation is possible through configuration changes alone. The mitigation strategy involves implementing proper input validation and output escaping techniques that align with WordPress security standards, specifically utilizing tag_escape() for HTML tag names rather than esc_attr(). This vulnerability demonstrates the importance of following established security frameworks such as CWE-79 (Cross-site Scripting) and aligns with ATT&CK technique T1566.002 (Phishing via Social Media) where attackers could leverage this vulnerability to redirect users to malicious sites. Additionally, administrators should consider implementing additional access controls and monitoring for unauthorized modifications to WordPress plugin configurations to prevent exploitation of similar vulnerabilities in other components.