# CVE-2023-2861: Qemu: 9pfs: improper access control on special files

> A malicious guest can escape the 9p shared folder by opening special device files, potentially leading to host privilege escalation or code execution.

- **Severity:** Medium 6.0 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Dec 2023
- **Updated:** 2 Aug 2024
- **Also known as:** AZL-32127, AZL-35167, DEBIAN-CVE-2023-2861, GHSA-6mxq-x623-25h9, UBUNTU-CVE-2023-2861

## What is CVE-2023-2861?

CVE-2023-2861 is a medium-severity path traversal vulnerability in Qemu Qemu, published on 6 Dec 2023. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A flaw was found in the 9p passthrough filesystem (9pfs) implementation in QEMU. The 9pfs server did not prohibit opening special files on the host side, potentially allowing a malicious client to escape from the exported 9p tree by creating and opening a device file in the shared folder.

Weakness: CWE-284 (Improper Access Control)

## Which versions are affected by CVE-2023-2861?

It affects 1 product.


Products: Qemu Qemu.

## How do I fix CVE-2023-2861?

Apply the vendor's patch.

## Is CVE-2023-2861 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2023-2861 exists.

## Other vulnerabilities in Qemu Qemu

- [CVE-2022-36648](https://insights.sbomify.com/CVE-2022-36648/): Null dereference in n/a (critical 10.0)
- [CVE-2015-8556](https://insights.sbomify.com/CVE-2015-8556/): Race condition in n/a (critical 10.0)
- [CVE-2009-3616](https://insights.sbomify.com/CVE-2009-3616/): Use after free in n/a (critical 9.9)
- [CVE-2019-12928](https://insights.sbomify.com/CVE-2019-12928/): Command injection in n/a (critical 9.8)
- [CVE-2019-12929](https://insights.sbomify.com/CVE-2019-12929/): Command injection in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-2861 and fix it if it is affected.

What it is: CVE-2023-2861 is a medium-severity path traversal vulnerability in Qemu Qemu, published on 6 Dec 2023. 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-2023-2861 exists.

Affected product: Qemu Qemu. 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-2023-2861/ (Markdown: https://insights.sbomify.com/CVE-2023-2861/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-2861
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-2861
- OSV: https://osv.dev/vulnerability/CVE-2023-2861

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-2861/
Summaries are generated and may contain mistakes; the official description above is the record.