Security researchers have found a vulnerability in a popular Unix GUI program that could enable an attacker to gain root privileges on a victim's computer.

The problem stems from a format string vulnerability in the Common Desktop Environment, an open-source GUI that runs on Unix and Linux operating systems.

Specifically, the ToolTalk message brokering service's RPC (Remote Procedure Call) database server—a component of the CDE—mishandles a certain error condition.

As such, an attacker can craft an RPC request that can cause the specific error condition. He could then overwrite portions of the victim's machine's memory, enabling him to execute code with the privileges of the RPC database server, which is typically root, according to a CERT advisory on the flaw.

The vulnerability, which was discovered by Internet Security Systems Inc.'s X-Force research team, affects numerous versions of Unix and Linux, including Caldera Inc.'s UnixWare and Open Linux and IBM's AIX 4.3 and 5.1. For a complete list of the vulnerable Unix and Linux implementations, see the CERT advisory at

Many of the affected vendors have already released patches and the others are working on them.