CVE-2026-120139 PostgreSQL tuple-size integer wraparound executes arbitrary code

This vulnerability is rated as an Important impact by Red Hat Product Security because an authenticated database user can achieve arbitrary code execution within the context of the postgres system user, compromising host and database integrity. While standard deployments on Red Hat Enterprise Linux confine the database process using a dedicated service account and SELinux, exploitation fully exposes the database engine and any data accessible to it. Exploitation requires network reachability and valid database login credentials to submit queries containing crafted, oversized row records. Unauthenticated remote attackers cannot trigger this issue directly.

Restrict network exposure to the PostgreSQL service so that only trusted client hosts and authorized administrators can establish connections.

1. Using firewalld, restrict incoming connections on PostgreSQL port 5432 to a trusted IP address or subnet:

```

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

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

firewall-cmd --reload

```

2. Alternatively, configure PostgreSQL to bind only to local interfaces by modifying `listen_addresses` in `/var/lib/pgsql/data/postgresql.conf`:

```

listen_addresses = 'localhost'

```

Apply the configuration change by restarting the service:

```

systemctl restart postgresql

```

Caveats:

Restricting network connectivity or interface binding prevents remote clients and applications outside the allowed subnet from connecting to the database.

Warning:

Restarting or reloading the PostgreSQL service terminates active client connections and temporarily interrupts database availability.