---
title: "CVE-2023-6683\n    | Ubuntu"
description: Ubuntu is an open source software operating system that runs from the
  desktop, to the cloud, to all your internet connected things.
url: https://ubuntu.com/security/CVE-2023-6683?format=md
keywords: index, follow
---

# CVE-2023-6683

Publication date 12 January 2024

Last updated 26 August 2025

---

Ubuntu priority

**Medium**

[Why this priority?](https://ubuntu.com/security/cves/about#priority )

## Cvss 3 Severity Score

**6.5 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2023-6683?format=md#impact-score)

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## Description

A flaw was found in the QEMU built-in VNC server while processing
ClientCutText messages. The qemu\_clipboard\_request() function can be
reached before vnc\_server\_cut\_text\_caps() was called and had the chance to
initialize the clipboard peer, leading to a NULL pointer dereference. This
could allow a malicious authenticated VNC client to crash QEMU and trigger
a denial of service.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| qemu | 24.04 LTS noble | Not affected |
| 23.10 mantic | Ignored end of life, was deferred [2024-06-17] |
| 23.04 lunar | Ignored end of life, was deferred [2024-06-17] |
| 22.04 LTS jammy | Fixed 1:6.2+dfsg-2ubuntu6.22 |
| 20.04 LTS focal | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)
* [Patch details](https://ubuntu.com/security/CVE-2023-6683?format=md#patch-details)

### Patch details

For informational purposes only. We recommend not to cherry-pick updates. [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)

| Package | Patch details |
| --- | --- |
| qemu | * Upstream:   [405484b](https://gitlab.com/qemu-project/qemu/-/commit/405484b29f6548c7b86549b0f961b906337aa68a) * Upstream:   [9c41658](https://gitlab.com/qemu-project/qemu/-/commit/9c416582611b7495bdddb4c5456c7acb64b78938) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

6.5 · Medium

* Base metrics

  | Parameter | Value |
  | --- | --- |
  | Attack vector | Network |
  | Attack complexity | Low |
  | Privileges required | Low |
  | User interaction | None |
  | Scope | Unchanged |
  | Confidentiality impact | None |
  | Integrity impact | None |
  | Availability impact | High |
* Scores

  | Parameter | Value |
  | --- | --- |
  | Base score | 6.5 · Medium |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-6683)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2023-6683)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2023-6683)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2023-6683)

### Related Ubuntu Security Notices (USN)

+ [USN-6954-1](https://usn.ubuntu.com/USN-6954-1)
+ QEMU vulnerabilities
+ 13 August 2024

### Other references

* <https://access.redhat.com/security/cve/CVE-2023-6683>
* <https://lists.nongnu.org/archive/html/qemu-devel/2024-01/msg02382.html>
* <https://www.cve.org/CVERecord?id=CVE-2023-6683>