CVE-2025-5400 is a critical SQL Injection vulnerability identified in the chaitak-gorai Blogbook software, specifically affecting the /user.php file's GET parameter handler. The vulnerability arises from improper sanitization of the 'u_id' argument, allowing an attacker to inject malicious SQL code remotely without any authentication or user interaction. This flaw enables an attacker to manipulate backend database queries, potentially leading to unauthorized data access, data modification, or even complete compromise of the database. The product uses a rolling release model, which complicates version tracking and patch management, and the vendor has not responded to disclosure attempts. Although the CVSS 4.0 score is 6.9 (medium severity), the nature of SQL injection vulnerabilities typically warrants heightened concern due to their potential impact. The vulnerability does not require privileges or user interaction, making exploitation easier. No known exploits are currently reported in the wild, but public disclosure increases the risk of exploitation attempts. The absence of patches or updates necessitates immediate mitigation efforts by users of Blogbook to prevent exploitation.

For European organizations using Blogbook, this vulnerability poses significant risks including unauthorized access to sensitive user data, potential data breaches, and disruption of service integrity. Exploitation could lead to exposure of personal data protected under GDPR, resulting in regulatory penalties and reputational damage. The ability to execute arbitrary SQL commands remotely without authentication increases the threat level, especially for organizations relying on Blogbook for user management or content delivery. The rolling release nature of the product and lack of vendor response complicate timely remediation, potentially leaving European entities exposed for extended periods. Attackers could leverage this vulnerability to pivot within networks, escalate privileges, or disrupt operations, impacting confidentiality, integrity, and availability of critical systems.

European organizations should immediately implement input validation and sanitization controls at the web application firewall (WAF) or reverse proxy level to filter and block malicious payloads targeting the 'u_id' parameter. Employing parameterized queries or prepared statements in any custom integrations with Blogbook can reduce injection risks. Network segmentation and strict access controls should be enforced to limit exposure of the Blogbook application to only trusted internal networks or VPN users. Continuous monitoring of logs for suspicious SQL query patterns related to 'u_id' parameters is essential to detect exploitation attempts early. Organizations should consider deploying runtime application self-protection (RASP) solutions to detect and block injection attacks in real time. Given the lack of vendor patches, organizations might explore temporary mitigation by disabling or restricting access to the vulnerable /user.php endpoint if feasible. Finally, organizations should prepare incident response plans specific to SQL injection attacks and ensure backups are current and tested for recovery.