# CVE-2018-1071: Memory corruption in zsh

> A local attacker can cause a denial of service via a stack-based buffer overflow in the zsh shell's hashcmd function.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Mar 2018
- **Updated:** 5 Aug 2024
- **Also known as:** ALPINE-CVE-2018-1071, DEBIAN-CVE-2018-1071, GHSA-xc49-qj7m-vpp4, UBUNTU-CVE-2018-1071

## What is CVE-2018-1071?

CVE-2018-1071 is a medium-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 9 Mar 2018. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

zsh through version 5.4.2 is vulnerable to a stack-based buffer overflow in the exec.c:hashcmd() function. A local attacker could exploit this to cause a denial of service.

Weakness: CWE-787 (Out-of-bounds Write), CWE-121 (Stack-based Buffer Overflow)

## Which versions are affected by CVE-2018-1071?

It affects 6 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Workstation, Zsh Zsh.

## How do I fix CVE-2018-1071?

Upgrade to a fixed version.

## Is CVE-2018-1071 being exploited?

There is no known exploitation of CVE-2018-1071 in the wild and no public exploit code.

## 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-2018-1071 and fix it if it is affected.

What it is: CVE-2018-1071 is a medium-severity memory corruption vulnerability in Canonical Ubuntu Linux, published on 9 Mar 2018. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2018-1071 in the wild and no public exploit code.

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-2018-1071/ (Markdown: https://insights.sbomify.com/CVE-2018-1071/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-1071
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-1071
- OSV: https://osv.dev/vulnerability/CVE-2018-1071

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-1071/
Summaries are generated and may contain mistakes; the official description above is the record.