CVE-2025-8293 is a medium-severity 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 via the 'date' parameter. The root cause is insufficient input sanitization and output escaping, which allows an authenticated attacker with Contributor-level access or higher to inject arbitrary malicious scripts into pages. These scripts execute whenever any user accesses the compromised page, potentially leading to session hijacking, defacement, or redirection to malicious sites. The vulnerability requires no user interaction beyond visiting the injected page and does not require administrative privileges, but does require authenticated contributor-level access, which is a moderate barrier. The CVSS v3.1 score is 6.4, reflecting network attack vector, low attack complexity, privileges required, no user interaction, and partial confidentiality and integrity impact but no availability impact. No known exploits are currently reported in the wild, and no patches have been published yet. The vulnerability is classified under CWE-79, indicating improper neutralization of input during web page generation, a common web application security flaw. This vulnerability is significant because WordPress is widely used across Europe, and plugins like Intl DateTime Calendar are often installed to enhance site functionality. Stored XSS vulnerabilities are particularly dangerous because injected scripts persist on the server and affect all users viewing the compromised content, increasing the attack surface and potential damage.

For European organizations, this vulnerability poses a risk primarily to websites using WordPress with the affected Intl DateTime Calendar plugin installed. The impact includes potential theft of user credentials, session tokens, or other sensitive information through malicious scripts executed in users' browsers. This can lead to unauthorized access, data breaches, and reputational damage. Since the vulnerability requires contributor-level access, attackers might exploit weak or stolen credentials or leverage social engineering to gain initial access. The persistent nature of stored XSS means that once exploited, the malicious script affects all visitors to the compromised page, including employees, customers, and partners, potentially leading to widespread compromise. European organizations in sectors such as e-commerce, government, education, and media that rely on WordPress for content management are at particular risk. The vulnerability could also be leveraged as a foothold for further attacks within an organization's network. Given the GDPR regulatory environment, exploitation leading to personal data exposure could result in significant legal and financial penalties.

1. Immediate mitigation should include restricting contributor-level access to trusted users only and auditing existing contributor accounts for suspicious activity. 2. Implement strict input validation and output encoding on the 'date' parameter within the plugin code to neutralize malicious scripts. Since no official patch is available yet, organizations should consider temporarily disabling or uninstalling the Intl DateTime Calendar plugin until a secure version is released. 3. Employ Web Application Firewalls (WAFs) with custom rules to detect and block malicious payloads targeting the 'date' parameter. 4. Conduct regular security audits and penetration testing focusing on plugin vulnerabilities and user privilege management. 5. Educate content contributors about phishing and credential security to reduce the risk of account compromise. 6. Monitor website logs for unusual activity indicative of XSS exploitation attempts. 7. Once a patch is released, apply it promptly and verify that the vulnerability is remediated. 8. Consider implementing Content Security Policy (CSP) headers to limit the impact of potential XSS attacks by restricting script execution sources.