CVE-2026-6467 PostgreSQL extension script schema mishandling executes arbitrary SQL

This vulnerability is rated as an Important impact because an authenticated user possessing database creation rights can escalate privileges to the database bootstrap superuser, resulting in complete administrative control over the PostgreSQL instance. While the flaw demands pre-existing database credentials with database-level CREATE permissions, the resulting blast radius encompasses full compromise of database confidentiality, integrity, and availability. In standard Red Hat Enterprise Linux deployments, unprivileged users do not receive database-level CREATE permissions by default, limiting exposure to systems configured for non-superuser extension administration or delegated multi-tenant operations.

Revoke database-level CREATE privileges from untrusted roles and restrict network access to the PostgreSQL service.

To prevent non-superusers from creating schemas or installing extensions, revoke the database creation privilege in PostgreSQL:

REVOKE CREATE ON DATABASE <database_name> FROM PUBLIC;

REVOKE CREATE ON DATABASE <database_name> FROM <role_name>;

Additionally, limit network exposure by restricting connections in pg_hba.conf to trusted hosts, or enforce firewall rules via firewalld:

firewall-cmd --permanent --zone=public --remove-service=postgresql

firewall-cmd --reload

If modifying pg_hba.conf, apply configuration changes using:

systemctl reload postgresql

Warning: Reloading the service or applying firewall rules will alter network connectivity and may disconnect clients that are not explicitly permitted. Revoking the CREATE privilege prevents affected accounts from defining new schemas or managing extensions until granted by a superuser.