---
title: "CVE-2017-5456\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-2017-5456?format=md
keywords: index, follow
---

# CVE-2017-5456

Publication date 20 April 2017

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**9.8 · Critical**

[Score breakdown](https://ubuntu.com/security/CVE-2017-5456?format=md#impact-score)

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## Description

A mechanism to bypass file system access protections in the sandbox using
the file system request constructor through an IPC message. This allows for
read and write access to the local file system. This vulnerability affects
Firefox ESR < 52.1 and Firefox < 53.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| firefox | 17.04 zesty | Fixed 53.0+build6-0ubuntu0.17.04.1 |
| 16.10 yakkety | Fixed 53.0+build6-0ubuntu0.16.10.1 |
| 16.04 LTS xenial | Fixed 53.0+build6-0ubuntu0.16.04.1 |
| 14.04 LTS trusty | Fixed 53.0+build6-0ubuntu0.14.04.1 |
| 12.04 LTS precise | Ignored |
| thunderbird | 17.04 zesty | Not affected |
| 16.10 yakkety | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Ignored end of life |

---

* [How can I get the fixes?](https://ubuntu.com/security/cves/about#security)
* [What do statuses mean?](https://ubuntu.com/security/cves/about#statuses)

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

9.8 · Critical

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 9.8 · Critical |
  | Exploitability score | - |
  | Impact score | - |

**Vector:** CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-5456)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-5456)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-5456)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-5456)

### Related Ubuntu Security Notices (USN)

+ [USN-3260-1](https://usn.ubuntu.com/USN-3260-1)
+ Firefox vulnerabilities
+ 21 April 2017

### Other references

* <https://www.mozilla.org/en-US/security/advisories/mfsa2017-10/#CVE-2017-5456>
* <https://www.cve.org/CVERecord?id=CVE-2017-5456>