As part of its Patch Tuesday releases, the company shipped a high-priority IE update (MS12-010) which covers four documented vulnerabilities that could be used in drive-by downloads with minimal user action. The update is rated "critical" for Internet Explorer 7, Internet Explorer 8, and Internet Explorer 9 on Windows client machines and Microsoft expects to see reliable exploit code published with the next 30 days.
The most severe vulnerabilities could allow remote code execution if a user views a specially crafted web page using Internet Explorer, Microsoft warned.
The company is also urging Windows users to pay special attention to MS12-013, a critical bulletin that fixes a flaw that could allow remote code execution if a user opens a specially crafted media file that is hosted on a website or sent as an email attachment.
From the bulletin:
A remote code execution vulnerability exists in the way that the msvcrt DLL calculates the size of a buffer in memory, allowing data to be copied into memory that has not been properly allocated. This vulnerability could allow remote code execution if a user opens a specially crafted media file. If a user is logged on with administrative user rights, an attacker who successfully exploited this vulnerability could take complete control of an affected system.
Microsoft also noted that any application that uses msvcrt.dll could be affected by this vulnerability, meaning that some third-party applications may also be vulnerable.
The company also shipped fixes for vulnerabilities in .Net Framework and Microsoft Silverlight.