9. VMware ESX Server Hypervisor Source Code Leaks
In late April, VMware acknowledged that a single file from its ESX server hypervisor source code had been posted online. The breach opened up the potential for a zero-day attack, and it ignited concerns that additional files might also be made public. Additional source code was then leaked in November by a hacker using the alias "Stun." Most of the specifics about either case were not publicly disclosed, making it difficult to assess the actual level of risk. But, a software update is believed to have resolved any potential issues.