Microsoft has given advance notification of at least 11 security fixes in its October Patch Tuesday update.

The update will contain four bulletins rated 'critical', six rated 'important' and one rated 'moderate'. The company has, however, added or removed bulletins in between the advance notification and the update release.

The four 'critical' bulletins include fixes for Windows, Internet Explorer, Excel and Microsoft Host Integration Server. All four address flaws which, if exploited, could allow an attacker to remotely execute code on a targeted system.

The six 'important' bulletins address flaws in the Windows operating system. If exploited, three of the flaws could allow for remote code execution, while the other three could allow an attacker to obtain elevated privileges.

The lone 'moderate' bulletin addresses a security issue in Office XP which could potentially lead to information disclosure. Other versions of the Office suite are not listed as vulnerable to the flaw.

Microsoft plans to release the October security update on 13 October.