# CVE-2016-2781: Privilege escalation in n/a

> Local attackers can escape chroot jails to the parent session via crafted TIOCSTI ioctl calls when using the --userspec option.

- **Severity:** Medium 4.6 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 7 Feb 2017
- **Updated:** 9 Jun 2025
- **Also known as:** AZL-34628, AZL-6355, DEBIAN-CVE-2016-2781, ECHO-e0c5-f2a2-174a, GHSA-vf3q-65gx-324p, UBUNTU-CVE-2016-2781

## What is CVE-2016-2781?

CVE-2016-2781 is a medium-severity vulnerability in n/a, published on 7 Feb 2017. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

chroot in GNU coreutils, when used with --userspec, allows local users to escape to the parent session via a crafted TIOCSTI ioctl call, which pushes characters to the terminal's input buffer.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2016-2781?

It affects 1 product.


Products: Gnu Coreutils.

## How do I fix CVE-2016-2781?

Apply the vendor's patch.

## Is CVE-2016-2781 being exploited?

There is no known exploitation of CVE-2016-2781 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2015-4042](https://insights.sbomify.com/CVE-2015-4042/): Integer overflow in n/a (critical 9.8)
- [CVE-2015-4041](https://insights.sbomify.com/CVE-2015-4041/): Memory corruption in n/a (high 7.8)
- [CVE-2017-18018](https://insights.sbomify.com/CVE-2017-18018/): Race condition in n/a (high 7.1)
- [CVE-2024-0684](https://insights.sbomify.com/CVE-2024-0684/): Coreutils: heap overflow in split --line-bytes with very long lines (medium 5.5)
- [CVE-2015-1865](https://insights.sbomify.com/CVE-2015-1865/): Race condition in n/a (medium 5.1)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-2781 and fix it if it is affected.

What it is: CVE-2016-2781 is a medium-severity vulnerability in n/a, published on 7 Feb 2017. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2016-2781 in the wild and no public exploit code.

Affected product: n/a. 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-2016-2781/ (Markdown: https://insights.sbomify.com/CVE-2016-2781/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-2781
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-2781
- OSV: https://osv.dev/vulnerability/CVE-2016-2781

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-2781/
Summaries are generated and may contain mistakes; the official description above is the record.