In utils.c in zsh before 5.4, symlink expansion had a buffer overflow.
{ "binaries": [ { "binary_version": "5.1.1-1ubuntu2.1", "binary_name": "zsh" }, { "binary_version": "5.1.1-1ubuntu2.1", "binary_name": "zsh-common" }, { "binary_version": "5.1.1-1ubuntu2.1", "binary_name": "zsh-dev" }, { "binary_version": "5.1.1-1ubuntu2.1", "binary_name": "zsh-static" } ], "availability": "No subscription required" }