Cloud computing is passing through development stage and with the passage process of development, cloud is also posing with security threats, challenges and risks. Lots of security threats, risks and challenges are directly or indirectly due to vulnerabilities in cloud environment. Virtualization is the process used in cloud computing through which software hardware is provided to the cloud users and also load balancing is possible in cloud resources and this process is also prone to various security threats and risks. Vulnerabilities and threats to the cloud services leads not only to the malpractices, misuse and exploitation of resources but also to the privacy violations and breaches in data. If these vulnerabilities are not properly identified and specific security measures are not adopted then cloud services will be adversely affected and hence there is dire need to address these vulnerabilities and threats at the cloud customer satisfaction level. In this paper various vulnerabilities and threats to the cloud computing are highlighted which are definitely instrumental to act as the basis of cloud computing security solutions.