It was discovered that unprivileged users were allowed to call internal character conversion functions. However, since these functions were not designed to be safe against malicious choices of argument values, this could potentially be exploited to execute arbitrary code with the privileges of the PostgreSQL server (user “postgres”). (CAN-2005-1409)
Another vulnerability was found in the “tsearch2” module of postgresql-contrib. This module declared several functions as internal, although they did not accept any internal argument; this breaks the type safety of “internal” by allowing users to construct SQL commands that invoke other functions accepting “internal” arguments. This could eventually be exploited to crash the server, or possibly even execute arbitrary code with the privileges of the PostgreSQL server. (CAN-2005-1410)
These vulnerabilities must also be fixed in all existing databases when upgrading. The post-installation script of the updated package attempts to do this automatically; if the package installs without any error, all existing databases have been updated to be safe against above vulnerabilities. Should the installation fail, please contact the Ubuntu security team (firstname.lastname@example.org) immediately.