CVE-2025-5587 in Appzend Plugin
Summary
by MITRE • 07/29/2025
The Appzend theme for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘progressbarLayout’ parameter in all versions up to, and including, 1.2.6 due to insufficient input sanitization and output escaping. 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 • 07/29/2025
The CVE-2025-5587 vulnerability affects the Appzend WordPress theme, representing a critical stored cross-site scripting flaw that undermines web application security. This vulnerability exists within the theme's handling of the 'progressbarLayout' parameter, which fails to implement proper input sanitization and output escaping mechanisms. The flaw specifically targets versions up to and including 1.2.6, making all installations within this range susceptible to exploitation. The vulnerability's classification as stored XSS indicates that malicious scripts are permanently stored on the server and executed whenever affected pages are accessed, creating a persistent threat vector that can compromise multiple users over time.
The technical implementation of this vulnerability stems from inadequate validation of user-supplied input within the theme's backend processing. When authenticated users with Contributor-level access or higher submit data containing malicious scripts through the 'progressbarLayout' parameter, the theme fails to sanitize this input properly before storing it in the database. This insufficient sanitization combined with inadequate output escaping creates a perfect storm for XSS exploitation, as the stored malicious content bypasses standard security filters and executes in the context of other users' browsers. The vulnerability's impact is amplified by the fact that it requires only Contributor-level privileges, which are often granted to users who should not have the ability to inject malicious code into the application's content.
The operational impact of CVE-2025-5587 extends beyond simple script execution, as it enables attackers to perform a wide range of malicious activities including credential theft, session hijacking, and data exfiltration. Once an attacker successfully injects malicious scripts, they can monitor user interactions, capture login credentials, redirect users to phishing sites, or even modify content displayed to other users. The stored nature of this vulnerability means that the malicious payload remains active even after the initial injection, potentially affecting all users who access pages containing the compromised content. This persistent threat can lead to prolonged unauthorized access and data compromise, making the vulnerability particularly dangerous in environments where multiple users regularly interact with the affected WordPress installation.
Organizations affected by this vulnerability should immediately implement multiple layers of mitigation strategies to protect their WordPress installations. The primary recommendation involves upgrading to the latest version of the Appzend theme where the vulnerability has been addressed through proper input sanitization and output escaping mechanisms. Additionally, administrators should implement strict role-based access controls to limit the number of users with Contributor-level privileges or higher, reducing the attack surface. Network-level protections such as web application firewalls and content security policies can provide additional defense in depth, while regular security audits and monitoring of user activities can help detect potential exploitation attempts. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws, and represents a clear violation of the principle of least privilege as defined in cybersecurity best practices, where user permissions should be strictly limited to prevent unauthorized code injection capabilities.