Microsoft Tuesday released five patches - four on them rated critical - as part of its monthly security update cycle. One of the patches affects Windows Vista. The four patches rated as critical, Microsoft's highest rating, involve the Windows operating system and Microsoft Content Management Server (CMS). They are: MS07-018, MS07-019, MS07-020 and MS07-021. The fifth patch, MS07-022, is rated important and addresses a vulnerability in Windows.

Some experts say it is patch MS07-021 that is the most significant because it is the only one that affects 32- and 64-bit Vista, Microsoft's newest operating system.

"We think 21 is critical because it is an indication that older vulnerable OS code is being reused in Vista," says Amol Sarwate, manager of vulnerability research for security vendor Qualys. "It definitely opens doors for attackers to try attacks that were used on older [Windows] code."

Full story.