# CVE-2016-9401: Use after free in n/a

> Local attackers can bypass restricted shell and trigger use-after-free in Bash, potentially leading to privilege escalation or code execution.

- **Severity:** Medium 6.2 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 23 Jan 2017
- **Updated:** 6 Aug 2025
- **Also known as:** ALPINE-CVE-2016-9401, DEBIAN-CVE-2016-9401, GHSA-888p-vvcc-q364, MGASA-2017-0005, SUSE-SU-2017:1317-1, SUSE-SU-2017:1337-1, UBUNTU-CVE-2016-9401

## What is CVE-2016-9401?

CVE-2016-9401 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 23 Jan 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

popd in bash might allow local users to bypass the restricted shell and cause a use-after-free via a crafted address.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2016-9401?

It affects 8 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `bash` | SUSE:Linux Enterprise Desktop 12 SP2 | All versions | 4.3-82.1 |
| `bash` | SUSE:Linux Enterprise Server 11 SP4 | All versions | 3.2-147.35.1 |
| `bash` | SUSE:Linux Enterprise Server 12 SP2 | All versions | 4.3-82.1 |
| `bash` | SUSE:Linux Enterprise Server for Raspberry Pi 12 SP2 | All versions | 4.3-82.1 |
| `bash` | SUSE:Linux Enterprise Server for SAP Applications 11 SP4 | All versions | 3.2-147.35.1 |
| `bash` | SUSE:Linux Enterprise Server for SAP Applications 12 SP2 | All versions | 4.3-82.1 |
| `bash` | SUSE:Linux Enterprise Software Development Kit 11 SP4 | All versions | 3.2-147.35.1 |
| `bash` | SUSE:Linux Enterprise Software Development Kit 12 SP2 | All versions | 4.3-82.1 |
| `bash` | SUSE:Linux Enterprise Workstation Extension 12 SP2 | All versions | 4.3-82.1 |

Products: Debian Debian Linux, Gnu Bash, 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-2016-9401?

Apply the vendor's patch.

## Is CVE-2016-9401 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-9401 exists.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-9401 and fix it if it is affected.

What it is: CVE-2016-9401 is a medium-severity use after free vulnerability in Debian Debian Linux, published on 23 Jan 2017. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2016-9401 exists.

Affected product: Debian Debian 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-2016-9401/ (Markdown: https://insights.sbomify.com/CVE-2016-9401/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-9401
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-9401
- OSV: https://osv.dev/vulnerability/CVE-2016-9401

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-9401/
Summaries are generated and may contain mistakes; the official description above is the record.