This update for zsh to version 5.6 fixes the following security issues: - CVE-2018-0502: The beginning of a #! script file was mishandled, potentially leading to an execve call to a program named on the second line . - CVE-2018-13259: Shebang lines exceeding 64 characters were truncated, potentially leading to an execve call to a program name that is a substring of the intended one .