Blocking Flash was the second such move by Apple in a month: On April 12, the company issued an OS X update that disabled automatic execution of Java applets by the Java browser plug-in. Apple took the step because of Flashback, a malware family that used a Java vulnerability to infect hundreds of thousands of Macs in a spree that still continues.
"As a security hardening measure, the Java browser plug-in and Java Web Start are deactivated if they are unused for 35 days," Apple said at the time.
Java Web Start is an Oracle technology that lets users single-click launch a Java app from within a browser without first downloading the app to the machine.
And Apple wasn't the only browser maker to recently block Adobe software. On Friday, Mozilla added the Adobe Reader plug-in to its Firefox blocklist, citing compatibility problems that resulted in blank pages appearing when users clicked on a link to a PDF document.
Mozilla maintains a blocklist for extensions or plug-ins that cause significant security or performance issues in Firefox. The browser automatically queries the blocklist and notifies users before disabling the targeted plug-in.
According to Mozilla, it's working with Adobe on a fix to Reader but will keep the plug-in on its blocklist until one is available.
Safari 5.1.7 can be downloaded from Apple's website. Mac users will be notified of the new version automatically by OS X's Software Update, while Windows users already running Safari will be alerted by a separate tool bundled with the browser.
Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer, on Google+ or subscribe to Gregg's RSS feed. His email address is email@example.com.
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