Microsoft will release 16 security bulletins fixing 34 vulnerabilities on its Patch Tuesday for June.

Among the bulletins, nine are rated as critical and affect Windows, Silverlight and the .NET Framework. Two of the bulletins will also cover Internet Explorer, with the first patch released for IE9. The other seven bulletins are rated as important and cover flaws in Windows, Office, SQL Server and Visual Studio.

Wolfgang Kandek, CTO at Qualys, said: “All versions of Excel in Microsoft Office will receive an update on both Windows and Mac OS X platforms, including even the most recent releases 2010 and 2011. Internet Explorer is covered by two bulletins that update version 6, 7, 8 and the newest version 9 as well.”

Jason Miller, data and security team leader at Shavlik, said: “Yes, this will be another large Patch Tuesday. We were hoping to see a new record number of security bulletins released, say something like in the 20+ bulletin count. We welcome, accept and look forward to the challenge of supporting as many patches as possible.

Adobe has also announced that it will offer quarterly security updates for its Acrobat and Reader products. It said: “Adobe is planning to release updates for Adobe Reader X (10.0.1) for Windows and Adobe Reader X (10.0.3) for Macintosh; Adobe Reader 9.4.3 and earlier versions for Windows and Macintosh; Adobe Acrobat X (10.0.3) for Windows and Macintosh; and Adobe Acrobat 9.4.2 and earlier versions for Windows and Macintosh to resolve critical security issues.”

Kandek said: “All in all, a big update and system administrators will need to plan closely as both workstations and servers are affected by the critical bulletins. In addition, applications such as Excel, Adobe Reader and Java will have to be taken into account this month.”

Miller said: “This is an important date as Adobe has some outstanding vulnerabilities they have been waiting to address until the next scheduled quarterly update. These vulnerabilities have been sitting idle as their newest products have a sandbox that protect against exploitation. With this many bulletins, stay tuned next Tuesday as there will be a lot of information to parse through.”