CVE-2025-8293 is a stored Cross-Site Scripting (XSS) vulnerability affecting the Intl DateTime Calendar plugin for WordPress, developed by Theerawat Patthawee. This vulnerability exists in all versions up to and including 1.0.1 due to improper neutralization of input during web page generation, specifically involving the 'date' parameter. The root cause is insufficient input sanitization and output escaping, which allows an authenticated attacker with Contributor-level privileges or higher to inject arbitrary malicious scripts into pages. These scripts are stored persistently and execute whenever any user accesses the compromised page, potentially leading to session hijacking, privilege escalation, or redirection to malicious sites. The vulnerability has a CVSS v3.1 base score of 6.4, indicating a medium severity level. The attack vector is network-based (remote), requires low attack complexity, and privileges at the Contributor level, but no user interaction is needed for exploitation. The scope is changed, meaning the vulnerability can affect resources beyond the initially compromised component. No known exploits are currently reported in the wild, and no patches have been published yet. This vulnerability falls under CWE-79, which covers improper neutralization of input leading to XSS attacks. Given the plugin’s integration with WordPress, a widely used content management system, the vulnerability could be leveraged to compromise websites that use this plugin, especially those that allow multiple contributors to publish content.

For European organizations, the impact of this vulnerability can be significant, particularly for those relying on WordPress sites with multiple contributors, such as media companies, educational institutions, and government portals. Exploitation could lead to unauthorized script execution, resulting in theft of user credentials, session tokens, or sensitive data, and potentially enabling further attacks such as privilege escalation or lateral movement within the network. The persistent nature of stored XSS increases the risk as malicious scripts remain active until the vulnerability is remediated. This can damage organizational reputation, lead to data breaches under GDPR regulations, and cause operational disruptions. Since the vulnerability requires Contributor-level access, insider threats or compromised contributor accounts pose a realistic risk vector. The medium severity score suggests moderate impact, but the changed scope and lack of user interaction requirement elevate the threat in environments with many users or visitors. Additionally, the absence of patches means organizations must rely on mitigation strategies until an official fix is available.

European organizations should implement several specific measures beyond generic advice: 1) Immediately audit and restrict Contributor-level access to trusted users only, enforcing strong authentication and monitoring for suspicious activity. 2) Employ Web Application Firewalls (WAFs) with custom rules to detect and block malicious payloads targeting the 'date' parameter in the Intl DateTime Calendar plugin. 3) Conduct thorough input validation and output encoding at the application level if possible, or disable the vulnerable plugin until a patch is released. 4) Monitor website content for unexpected script injections or anomalies in pages generated by the plugin. 5) Educate contributors on secure content publishing practices and the risks of XSS. 6) Keep WordPress core and all plugins updated and subscribe to vulnerability disclosure feeds for timely patch deployment. 7) Consider isolating or sandboxing the affected WordPress instances to limit potential lateral movement in case of compromise. 8) Implement Content Security Policy (CSP) headers to restrict execution of unauthorized scripts on affected sites.