CVE-2026-120147 PostgreSQL dblink reentrant disconnect use-after-free executes arbitrary code

Red Hat has evaluated this vulnerability as an Important severity risk because an authenticated database user capable of creating database objects can achieve arbitrary code execution under the operating system identity of the PostgreSQL server daemon. While the flaw permits severe host-level compromise, exploitation is bounded by the prerequisite of having existing database access, permissions to declare custom types, and an active installation of the optional dblink extension. In standard Red Hat Enterprise Linux configurations, dblink is not enabled by default.

If the dblink extension is not required by your applications, remove it from all affected databases using the following command in a psql session:

DROP EXTENSION IF EXISTS dblink CASCADE;

If the extension is required, mitigate exposure by preventing untrusted database users from defining custom objects (such as types and functions), for example by revoking create privileges on public schemas:

REVOKE CREATE ON SCHEMA public FROM PUBLIC;

Additionally, revoke execute permissions on dblink functions from untrusted roles.

Caveats: Dropping the extension or revoking schema permissions will break applications and automated tasks that rely on dblink cross-database queries or object creation. These SQL operations take effect immediately and do not require a database service restart or reload.