CVE-2025-5587 is a medium-severity Stored Cross-Site Scripting (XSS) vulnerability affecting the Appzend WordPress theme developed by sparklewpthemes. The vulnerability arises from improper neutralization of input during web page generation, specifically via the 'progressbarLayout' parameter. This parameter is insufficiently sanitized and escaped, allowing an authenticated attacker with Contributor-level privileges or higher to inject arbitrary JavaScript code into pages generated by the theme. Once injected, the malicious script executes whenever any user accesses the compromised page, potentially leading to session hijacking, privilege escalation, or other malicious activities. The vulnerability affects all versions up to and including version 1.2.6 of the Appzend theme. The CVSS 3.1 base score is 6.4, reflecting a network attack vector, low attack complexity, requiring privileges but no user interaction, and impacting confidentiality and integrity with a scope change. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability was publicly disclosed on July 29, 2025, with the CVE reserved on June 3, 2025. The CWE classification is CWE-79, which is a common and well-understood web application vulnerability type.

For European organizations using WordPress websites with the Appzend theme, this vulnerability poses a significant risk. Attackers with Contributor-level access—often achievable through compromised accounts or weak credential management—can inject persistent malicious scripts. This can lead to theft of user credentials, unauthorized actions performed on behalf of users, defacement, or distribution of malware. Given the widespread use of WordPress in Europe for corporate, governmental, and e-commerce sites, exploitation could undermine trust, cause data breaches, and disrupt business operations. The confidentiality and integrity of user data are at risk, particularly for sites handling sensitive information or user accounts. The lack of user interaction required for exploitation increases the threat level. Although availability is not directly impacted, the reputational damage and potential regulatory consequences under GDPR for data breaches could be severe.

European organizations should take immediate steps to mitigate this vulnerability. First, they should verify if their WordPress installations use the Appzend theme version 1.2.6 or earlier and plan to upgrade to a patched version once available. In the absence of an official patch, organizations can implement temporary mitigations such as disabling or restricting the 'progressbarLayout' parameter usage, applying custom input validation and output encoding on this parameter, or restricting Contributor-level user capabilities to trusted personnel only. Additionally, implementing Web Application Firewalls (WAFs) with rules to detect and block suspicious script injections targeting this parameter can reduce risk. Regular auditing of user accounts and enforcing strong authentication mechanisms (e.g., MFA) will limit the risk of account compromise. Monitoring website content for unauthorized script injections and maintaining up-to-date backups will aid in rapid recovery if exploitation occurs.