---
id: CVE-2024-41815
aliases:
  - RUSTSEC-2024-0446
  - GHSA-vx24-x4mv-vwr5
title: Shell expansion in custom commands
summary: Shell expansion in custom commands
severity: high
cvss: 7.4
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H'
vendor: starship
product: starship
ecosystem: rust
affected:
  - 'starship >= 1.0.1-0, < 1.20.0'
patched:
  - starship 1.20.0
published: '2024-07-26'
updated: '2026-10-12'
sourceUpdated: '2026-10-12T18:00:11.506829501Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/RUSTSEC-2024-0446'
references:
  - url: 'https://crates.io/crates/starship'
  - url: 'https://rustsec.org/advisories/RUSTSEC-2024-0446.html'
  - url: >-
      https://github.com/starship/starship/commit/cfc58161e0ec595db90af686ad77a73df6d44d74
tags:
  - osv
  - rust
epss: 0.00463
epssPercentile: 0.40281
ingestedAt: '2026-10-13T11:45:30.175Z'
---

## Overview

## Summary

Undocumented and unpredictable shell expansion and/or quoting
rules make it easily to accidentally cause shell injection
when using custom commands with starship in bash.

## Details

I wanted to show the git commit name in my prompt (I use bash), so I added a command:

```
[custom.git_commit_name]
command = 'git show -s --format="%<(25,mtrunc)%s"'
style = "italic"
when = true
```

To my surprise, when I had a commit with backticks in it,
the backticks were expanded. e.g.:

```
touch foo
git add foo
git commit -m '`ls`'
```

Thankfully I noticed it on my own commit before checking out
someone's code whose commit message was

`rm -rf /important/stuff`

The documentation says:

Command output is printed unescaped to the prompt

```
    Whatever output the command generates is printed unmodified in the prompt.
    This means if the output contains special sequences that are interpreted
    by your shell they will be expanded when displayed. These special
    sequences are shell specific, e.g. you can write a command module that
    writes bash sequences, e.g. \h, but this module will not work in a fish
    or zsh shell.

    Format strings can also contain shell specific prompt sequences, e.g. Bash, Zsh.
```

However, it doesn't specifically mention shell injection with $()
and backticks; it just mentions the prompt escape sequences, and
the link doesn't suggest any shell injection possibilities either.

Furthermore, I can't even figure out how to properly escape things,
because simply changing the command to

```
command = 'printf %q "$(git show -s --format="%<(25,mtrunc)%s")"'
```

doesn't work, as it's also adding a backslash before spaces. I also
tried `use_stdin=false`

I'm not 100% sure this qualifies as a vulnerability, but I feel it is not
documented well enough to warn unsuspecting users, and it certainly is
not documented how to properly quote things, because after 15-30 minutes
of trying, I can't figure it out.

I see some past commits about fixing shell injection with $, and it does
seem like the problem doesn't exist in build-in modules like git branch.

## PoC

Have some custom command which prints out information from a potentially untrusted/unverified source.

```
[custom.git_commit_name]
command = 'git show -s --format="%<(25,mtrunc)%s"'
style = "italic"
when = true
```

## Impact

People with custom commands, so the scope is limited, and without knowledge
of people's commands, it could be hard to target people. The only one I saw
in the example custom commands that may be vulnerable is the playerctl one.

## Affected packages

- `starship >= 1.0.1-0, < 1.20.0`

## Remediation

Upgrade to a patched release:

- `starship 1.20.0`