---
title: "CVE-2023-3347\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-2023-3347?format=md
keywords: index, follow
---

# CVE-2023-3347

Publication date 19 July 2023

Last updated 26 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.9 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2023-3347?format=md#impact-score)

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## Description

A vulnerability was found in Samba's SMB2 packet signing mechanism. The
SMB2 packet signing is not enforced if an admin configured "server signing
= required" or for SMB2 connections to Domain Controllers where SMB2 packet
signing is mandatory. This flaw allows an attacker to perform attacks, such
as a man-in-the-middle attack, by intercepting the network traffic and
modifying the SMB2 messages between client and server, affecting the
integrity of the data.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2023-3347?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| samba | 23.04 lunar | Fixed 2:4.17.7+dfsg-1ubuntu1.1 |
| 22.10 kinetic | Not affected |
| 22.04 LTS jammy | Not affected |
| 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)

## Notes

---

### [mdeslaur](https://launchpad.net/~mdeslaur)

4.17.0 and higher only

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.9 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.9 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-3347)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2023-3347)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2023-3347)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2023-3347)

### Related Ubuntu Security Notices (USN)

+ [USN-6238-1](https://usn.ubuntu.com/USN-6238-1)
+ Samba vulnerabilities
+ 19 July 2023

### Other references

* <https://www.samba.org/samba/security/CVE-2023-3347.html>
* <https://www.cve.org/CVERecord?id=CVE-2023-3347>