Public Vulnerability Reports

IBM AIX pioout BSS Buffer Overflow Vulnerability



The pioout program is a set-uid root application, installed by default under multiple versions of IBM AIX, that is used to interface with the printer driver. For more information, visit the following URL.


Local exploitation of a buffer overflow vulnerability in IBM Corp.'s AIX operating system 'pioout' program allows attackers to execute arbitrary code with root privileges.

The vulnerability exists due to insufficient input validation when copying user-supplied data to a fixed-size buffer. By passing a long string as a command line option, an attacker can cause an exploitable buffer overflow.


Exploitation of this vulnerability results in the execution of arbitrary code with root privileges. In order to exploit this vulnerability, an attacker must have access to execute the set-uid root 'pioout' program.


iDefense has confirmed the existence of this vulnerability in version 5.2 and 5.3 of AIX with all patches applied as of November 29th, 2007. Previous versions are suspected to be affected.


Removing the set-uid bit from the binary will prevent exploitation, but will also make the program unusable by non-root users.


IBM Corp. has addressed this vulnerability by releasing interim fixes. More information can be found via the Bulletins tab of IBM's Subscription Service for UNIX and Linux servers. You can reach this service by clicking the URL shown below.


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-5764 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


11/29/2007 Initial vendor notification
12/03/2007 Initial vendor response
01/23/2008 Coordinated public disclosure


The discoverer of this vulnerability wishes to remain anonymous.

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