Microsoft on Tuesday patched a record number of security vulnerabilities, plugging 31 holes in its Windows operating systems, Internet Explorer browser, and other products.
The updates were packaged into 10 bulletins, five of which were rated "critical," Microsoft's top severity rating. What's more, Microsoft warned that 15 of the 31 flaws are likely to be reliably exploited in the next 30 days. The monster patch batch bested Microsoft's previous record in December, when the company fixed 28 vulnerabilities.
Among the patches was one plugging eight vulnerabilities in IE, including one vuln that allowed a hacker to remotely execute arbitrary code on a machine running the latest version of IE 8 at the Pwn2Own hacker contest in March. Another patch fixed the WebDAV vulnerability in Microsoft's Internet Information Services server, which allowed hackers to access restricted parts of a server by plugging a specially manipulated address into a web browser.
Microsoft also fixed a variety of vulnerabilities in its Office application suite, including several for Macs that weren't ready for release during last month's Patch Tuesday.
The patch release coincided with security updates released by Adobe Software for its Reader and Acrobat applications. It was the beginning of Adobe's quarterly release cycle designed to make life easier on people who administer large fleets of computers. The Adobe fixes won't be available for Unix until June 16, a delay that's unfortunate since it gives hackers seven days to reverse engineer the Windows and Mac patches and create exploits for machines that are still unprotected.
This story was updated to correct details about Microsoft Office patches..