CVE-2026-2004 is a vulnerability identified in the PostgreSQL database system, specifically within the intarray extension's selectivity estimator function. The root cause is the improper validation of the type of input provided to this function. This flaw allows an attacker who can create database objects—such as functions or operators—to execute arbitrary code at the operating system level with the privileges of the database server process. Since PostgreSQL often runs with elevated privileges, this can lead to full system compromise. The vulnerability affects all PostgreSQL versions before 18.2, 17.8, 16.12, 15.16, and 14.21. The CVSS 3.1 base score of 8.8 indicates a high-severity issue with network attack vector (AV:N), low attack complexity (AC:L), requiring privileges (PR:L) but no user interaction (UI:N), and impacting confidentiality, integrity, and availability (C:H/I:H/A:H). Although no public exploits are currently known, the potential for damage is significant. The vulnerability is particularly dangerous in environments where users have the ability to create database objects, such as in shared hosting or multi-tenant cloud services. The lack of input type validation in the selectivity estimator function allows crafted inputs to trigger execution paths that lead to arbitrary code execution. This can be exploited to escalate privileges, steal sensitive data, or disrupt database operations.

For European organizations, this vulnerability poses a serious risk to data confidentiality, integrity, and system availability. PostgreSQL is widely used across Europe in government, finance, healthcare, and enterprise sectors. Exploitation could lead to unauthorized access to sensitive personal and corporate data, violating GDPR and other regulatory requirements. The ability to execute arbitrary code as the database OS user could allow attackers to pivot within networks, deploy ransomware, or disrupt critical services. Organizations with multi-tenant environments or those exposing PostgreSQL instances to untrusted users are particularly vulnerable. The impact extends beyond data loss to potential operational downtime and reputational damage. Given the high CVSS score and the nature of the vulnerability, the threat is critical for any European entity relying on affected PostgreSQL versions without mitigations.

1. Immediately upgrade PostgreSQL to the fixed versions: 18.2, 17.8, 16.12, 15.16, or 14.21 as applicable. 2. Restrict the ability to create database objects (functions, operators) to trusted, highly privileged users only. 3. Implement strict role-based access control (RBAC) within PostgreSQL to minimize privilege exposure. 4. Monitor database logs for unusual object creation or function execution activities. 5. Employ network segmentation and firewall rules to limit access to PostgreSQL instances, especially from untrusted networks. 6. Use security extensions or tools that can detect anomalous behavior or code execution attempts within the database environment. 7. Regularly audit PostgreSQL configurations and installed extensions to ensure compliance with security best practices. 8. Consider deploying PostgreSQL in containerized or sandboxed environments to limit OS-level impact in case of exploitation. 9. Educate database administrators and developers about the risks of granting object creation privileges to untrusted users. 10. Maintain up-to-date backups and incident response plans tailored to database compromise scenarios.