fish is a smart and user-friendly command line shell for macOS, Linux, and the rest of the family. fish shell uses certain Unicode non-characters internally for marking wildcards and expansions. It will incorrectly allow these markers to be read on command substitution output, rather than transforming them into a safe internal representation. While this may cause unexpected behavior with direct input (for example, echo \UFDD2HOME has the same output as echo $HOME), this may become a minor security problem if the output is being fed from an external program into a command substitution where this output may not be expected. This design flaw was introduced in very early versions of fish, predating the version control system, and is thought to be present in every version of fish released in the last 15 years or more, although with different characters. Code execution does not appear to be possible, but denial of service (through large brace expansion) or information disclosure (such as va…

fish is a command line shell. fish version 3.1.0 through version 3.3.1 is vulnerable to arbitrary code execution. git repositories can contain per-repository configuration that change the behavior of git, including running arbitrary commands. When using the default configuration of fish, changing to a directory automatically runs `git` commands in order to display information about the current repository in the prompt. If an attacker can convince a user to change their current directory into one controlled by the attacker, such as on a shared file system or extracted archive, fish will run arbitrary commands under the attacker's control. This problem has been fixed in fish 3.4.0. Note that running git in these directories, including using the git tab completion, remains a potential trigger for this issue. As a workaround, remove the `fish_git_prompt` function from the prompt.

The psub function in fish (aka fish-shell) 1.16.0 before 2.1.1 does not properly create temporary files, which allows local users to execute arbitrary commands via a temporary file with a predictable name.

fish (aka fish-shell) 2.0.0 before 2.1.1 does not restrict access to the configuration service (aka fish_config), which allows remote attackers to execute arbitrary code via unspecified vectors, as demonstrated by set_prompt.

The funced function in fish (aka fish-shell) 1.23.0 before 2.1.1 does not properly create temporary files, which allows local users to gain privileges via a temporary file with a predictable name.

fish before 2.1.1 allows local users to write to arbitrary files via a symlink attack on (1) /tmp/fishd.log.%s, (2) /tmp/.pac-cache.$USER, (3) /tmp/.yum-cache.$USER, or (4) /tmp/.rpm-cache.$USER.

fish (aka fish-shell) 1.16.0 before 2.1.1 does not properly check the credentials, which allows local users to gain privileges via the universal variable socket, related to /tmp/fishd.socket.user permissions.