Microsoft · Windows Vista · CVE-2012-0157
**Name of the Vulnerable Software and Affected Versions**
win32k.sys in Microsoft Windows versions prior to the fixed version
**Description**
The issue arises from the improper handling of window messaging by the win32k.sys kernel-mode driver, allowing local users to gain privileges via a crafted application that calls the `PostMessage` function. This could enable an attacker to run arbitrary code in kernel mode, potentially leading to the installation of programs, viewing, changing, or deleting data, or creating new accounts with full administrative rights.
**Recommendations**
For Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, and Windows 7 Gold and SP1, update to a version that includes the fix for the PostMessage function vulnerability.
As a temporary workaround, consider restricting the use of the `PostMessage` function until a patch is available.