CVE-2026-6460 PostgreSQL type confusion after ALTER ... SET DATA TYPE executes arbitrary code

This vulnerability is rated as Important because an authenticated user with object-creation privileges can execute arbitrary code under the operating system account running the PostgreSQL service. Although this allows full compromise of the database daemon host environment, exploitation requires prior authentication to the database and permissions to execute data definition statements, which precludes unauthenticated remote attacks. In standard Red Hat deployments, database instances should be configured so that untrusted users are not granted table creation or administrative schema alteration privileges.

Limit exposure to the PostgreSQL service by restricting network connectivity to trusted administrative hosts and revoking object-creation privileges from untrusted database accounts.

1. Restrict network reachability to trusted IP addresses using firewalld:

```

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

firewall-cmd --permanent --zone=trusted --add-source=<trusted_ip_or_network>

firewall-cmd --reload

```

2. Revoke table creation privileges from untrusted database accounts within PostgreSQL:

```

REVOKE CREATE ON SCHEMA public FROM PUBLIC;

```

Caveats: Restricting network access prevents unapproved remote hosts from connecting to the database server. Revoking schema creation privileges may disrupt applications that require dynamic creation of temporary or permanent tables until explicit schema permissions are assigned.

Warning: Reloading the firewall configuration using `firewall-cmd --reload` alters active packet filtering rules immediately and may disrupt existing network sessions.