CVE-2025-26855 is a SQL injection vulnerability identified in the Articles Calendar extension versions 1.0.0 through 1.0.1.0007 for the Joomla content management system. This vulnerability arises from improper neutralization of special elements used in SQL commands (CWE-89), allowing an attacker to inject arbitrary SQL code into the backend database queries executed by the extension. Exploitation of this flaw could enable an attacker to manipulate the database, potentially leading to unauthorized data disclosure, data modification, or even complete compromise of the underlying database server. The vulnerability affects the Articles Calendar extension, which is used to display and manage calendar-based article content within Joomla websites. Since Joomla is a widely used CMS, especially among small to medium-sized enterprises and public sector websites in Europe, the presence of this vulnerability in a popular extension poses a significant risk. The lack of an available patch at the time of publication increases the urgency for organizations to implement mitigations. No known exploits are currently reported in the wild, but the nature of SQL injection vulnerabilities makes them attractive targets for attackers due to the potential for high-impact exploitation. The vulnerability does not require authentication or user interaction, increasing its risk profile. Given the technical details, attackers can craft malicious input that is improperly sanitized by the extension, leading to execution of arbitrary SQL commands on the backend database.

For European organizations, the impact of this vulnerability can be substantial. Many European businesses, government agencies, and non-profits rely on Joomla for their web presence, and extensions like Articles Calendar enhance site functionality. Exploitation could lead to unauthorized access to sensitive data, including personal data protected under GDPR, resulting in legal and financial repercussions. Data integrity could be compromised, affecting the reliability of published content and internal records. Availability of the website could also be disrupted if attackers execute destructive SQL commands. The reputational damage from a successful attack could be severe, especially for public sector entities and organizations handling sensitive citizen or customer information. Additionally, the lack of a patch means organizations must rely on alternative mitigations, increasing operational complexity and risk.

European organizations should immediately audit their Joomla installations to identify the presence of the Articles Calendar extension in affected versions (1.0.0 to 1.0.1.0007). If found, they should consider disabling or uninstalling the extension until a vendor patch is released. Web application firewalls (WAFs) with SQL injection detection and prevention capabilities should be deployed or updated to include rules targeting this specific vulnerability pattern. Input validation and sanitization should be enforced at the application level wherever possible. Organizations should monitor web server and database logs for suspicious activity indicative of SQL injection attempts. Regular backups of website data and databases should be maintained to enable recovery in case of compromise. Additionally, organizations should follow Joomla community channels for updates and apply patches promptly once available. Network segmentation and least privilege principles should be enforced to limit the impact of any successful exploitation.