---
title: "CVE-2018-6334\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-2018-6334?format=md
keywords: index, follow
---

# CVE-2018-6334

Publication date 31 December 2018

Last updated 26 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-2018-6334?format=md#impact-score)

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## Description

Multipart-file uploads call variables to be improperly registered in the
global scope. In cases where variables are not declared explicitly before
being used this can lead to unexpected behavior. This affects all supported
versions of HHVM prior to the patch (3.25.1, 3.24.5, and 3.21.9 and below).

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| hhvm | 26.04 LTS resolute | Not in release |
| 25.10 questing | Not in release |
| 25.04 plucky | Not in release |
| 24.10 oracular | Not in release |
| 24.04 LTS noble | Not in release |
| 23.10 mantic | Not in release |
| 23.04 lunar | Not in release |
| 22.10 kinetic | Not in release |
| 22.04 LTS jammy | Not in release |
| 21.10 impish | Not in release |
| 21.04 hirsute | Not in release |
| 20.10 groovy | Not in release |
| 20.04 LTS focal | Not in release |
| 19.10 eoan | Not in release |
| 19.04 disco | Not in release |
| 18.10 cosmic | Not in release |
| 18.04 LTS bionic | Needs evaluation |
| 17.10 artful | Ignored end of life |
| 16.04 LTS xenial | Needs evaluation |
| 14.04 LTS trusty | Not in release |

---

* [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-2018-6334?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 |
| --- | --- |
| hhvm | * Upstream:   [6937de5](https://github.com/facebook/hhvm/commit/6937de5544c3eead3466b75020d8382080ed0cff) |

## 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:3.1/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-2018-6334)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2018-6334)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2018-6334)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2018-6334)

### Other references

* <https://hhvm.com/blog/2018/03/30/hhvm-3.25.2.html>
* <https://www.cve.org/CVERecord?id=CVE-2018-6334>