# CVE-2018-17456: Command injection in n/a

> Attackers can execute arbitrary code by crafting a malicious .gitmodules file with a URL starting with a dash during recursive cloning.

- **Severity:** Critical 9.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Oct 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2018-17456, CLEANSTART-2026-QG10579, DEBIAN-CVE-2018-17456, DLA-1533-1, DSA-4311-1, GHSA-g986-jp62-5xq6, MGASA-2018-0395, RHSA-2018:3408, RHSA-2018:3541, RHSA-2020:0316, SUSE-SU-2018:3150-1, SUSE-SU-2018:4009-1, SUSE-SU-2018:4088-1, SUSE-SU-2018:4088-2, SUSE-SU-2018:4088-3, UBUNTU-CVE-2018-17456, USN-3791-1

## What is CVE-2018-17456?

CVE-2018-17456 is a critical command injection vulnerability in Canonical Ubuntu Linux, published on 6 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Git before 2.14.5, 2.15.x before 2.15.3, 2.16.x before 2.16.5, 2.17.x before 2.17.2, 2.18.x before 2.18.1, and 2.19.x before 2.19.1 allows remote code execution during processing of a recursive "git clone" of a superproject if a .gitmodules file has a URL field beginning with a '-' character.

Weakness: CWE-88 (Improper Neutralization of Argument Delimiters in a Command)

## Which versions are affected by CVE-2018-17456?

It affects 11 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `emacs-git` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git-el` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-all` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-cvs` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-daemon` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-debuginfo` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-email` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-gui` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `git-svn` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `gitk` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `gitweb` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `perl-Git` | Red Hat:enterprise_linux:6::client | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git-el` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-all` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-cvs` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-daemon` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-debuginfo` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-email` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-gui` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `git-svn` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `gitk` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `gitweb` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `perl-Git` | Red Hat:enterprise_linux:6::computenode | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git-el` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-all` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-cvs` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-daemon` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-debuginfo` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-email` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-gui` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `git-svn` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `gitk` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `gitweb` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `perl-Git` | Red Hat:enterprise_linux:6::server | All versions | 0:1.7.1-10.el6_10 |
| `emacs-git` | Red Hat:enterprise_linux:6::workstation | All versions | 0:1.7.1-10.el6_10 |

Products: Canonical Ubuntu Linux, Debian Debian Linux, Git-Scm Git, Redhat Ansible Tower, Redhat Enterprise Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-17456?

Upgrade to a fixed version.

## Is CVE-2018-17456 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-17456 exists.

Public exploit code:

- CVE-2018-17456漏洞复现（PoC+Exp） (github_poc): https://github.com/AnonymKing/CVE-2018-17456
- Git Submodule - Arbitrary Code Execution (PoC) (exploitdb)
- Malicious Git HTTP Server For CVE-2018-17456 (metasploit)
- Git Submodule - Arbitrary Code Execution (exploitdb)
- 1-day (github_poc): https://github.com/shpik-kr/CVE-2018-17456
- https://github.com/matlink/CVE-2018-17456 (github_poc): https://github.com/matlink/CVE-2018-17456

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-17456 and fix it if it is affected.

What it is: CVE-2018-17456 is a critical command injection vulnerability in Canonical Ubuntu Linux, published on 6 Oct 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2018-17456 exists.

Affected product: Canonical Ubuntu Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2018-17456/ (Markdown: https://insights.sbomify.com/CVE-2018-17456/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-17456
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-17456
- OSV: https://osv.dev/vulnerability/CVE-2018-17456

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-17456/
Summaries are generated and may contain mistakes; the official description above is the record.