zsh before 5.0.7 allows evaluation of the initial values of integer variables imported from the environment (instead of treating them as literal numbers)

zsh before 5.0.7 allows evaluation of the initial values of integer variables imported from the environment (instead of treating them as literal numbers). That could allow local privilege escalation, under some specific and atypical conditions where zsh is being invoked in privilege-elevation contexts when the environment has not been properly sanitized, such as when zsh is invoked by sudo on systems where "env_reset" has been disabled.