There’s patching work ahead for users of Safari and Firefox web browsers as both Apple and Mozilla issued updates late Wednesday to plug security holes in their software. Apple’s patch fixes four flaws in the Windows version of Safari and two in the Mac version. This includes the security flaw that allowed a hacker to crack OS X in less than two minutes at last month’s CanSecWest security conference.

Mozilla’s update addresses a single critical vulnerability with the way Firefox handles “Javascript garbage collection,” causing crashes and evidence of memory corruption. The company says that though there is no evidence that this particular flaw is exploitable, surfers are advised to update to version 2.0.0.14 as there have been instances in the past when attackers were able to exploit similar problems.