CVE-2017-18205
In builtin.c in zsh before 5.4, when sh compatibility mode is used, there is a NULL pointer dereference during processing of the cd command with no argument if HOME is not set.
Date published : 2018-02-27
https://security.gentoo.org/glsa/201805-10
https://sourceforge.net/p/zsh/code/ci/eb783754bdb74377f3cea4ceca9c23a02ea1bf58