April's Microsoft Patch Tuesday sees 11 fixes

Microsoft has issued the April release of its monthly security update.

The company on Tuesday issued 11 bulletins which fix a total of 25 security vulnerabilities in Windows, Office and Exchange.

Of the eleven bulletins, five address vulnerabilities which have been labelled by the company as 'critical.' If exploited, the vulnerabilities could potentially allow an attacker to remotely execute code on the targeted system without user notification.

Each of the five bulletins addresses vulnerabilities in the Windows operating system itself. While the severity of the vulnerabilities can very by version, the update includes fixes for flaws deemed critical in Windows 2000, XP, Server 2003, Vista, Windows 7 and Server 2008 R2.

Another five bulletins address issues rated 'important' by Microsoft. Those updates include flaws in Windows as well as Exchange Server and the Office XP. 2003 and 2007 versions. Risks of the vulnerabilities included remote code execution, elevation of privilege and denial of service attacks.

The last of the bulletins was rated as a 'moderate' risk and addressed a spoofing vulnerability in the ISATAP component for Windows XP, Server 2003, Vista and Server 2008 versions prior to R2. Windows 7 and Server 2008 R2 have been confirmed to not be at risk.