image_optimizer 1.3.0 through 1.9.0 OS Command Injection via identify_format

The image_optimizer Ruby gem 1.3.0 through 1.9.0 contains an OS command injection vulnerability in ImageOptimizer#identify_format that allows attackers to execute commands by supplying a crafted image path when the identify option is enabled. Attackers controlling the path, such as an uploaded file name, can append shell metacharacters like ';' that are executed via Ruby backticks with the Ruby process privileges.