---
title: "CVE-2019-6706\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-2019-6706?format=md
keywords: index, follow
---

# CVE-2019-6706

Publication date 23 January 2019

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**7.5 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2019-6706?format=md#impact-score)

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## Description

Lua 5.3.5 has a use-after-free in lua\_upvaluejoin in lapi.c. For example, a
crash outcome might be achieved by an attacker who is able to trigger a
debug.upvaluejoin call in which the arguments have certain relationships.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2019-6706?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| lua5.1 | 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |
| lua5.2 | 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not affected |
| lua5.3 | 18.10 cosmic | Fixed 5.3.3-1ubuntu0.18.10.1 |
| 18.04 LTS bionic | Fixed 5.3.3-1ubuntu0.18.04.1 |
| 16.04 LTS xenial | Fixed 5.3.1-1ubuntu2.1 |
| 14.04 LTS trusty | Not in release |
| lua50 | 18.10 cosmic | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not affected |
| 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)

## Notes

---

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

as of 2019-02-28, proposed fix not committed
per debian, 5.0, 5.1 and 5.2 aren't affected

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.5 · High

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.5 · High |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-6706)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2019-6706)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2019-6706)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2019-6706)

### Related Ubuntu Security Notices (USN)

+ [USN-3941-1](https://usn.ubuntu.com/USN-3941-1)
+ Lua vulnerability
+ 8 April 2019

### Other references

* <http://lua.2524044.n2.nabble.com/Bug-Report-Use-after-free-in-debug-upvaluejoin-tc7685506.html>
* <http://lua.2524044.n2.nabble.com/CVE-2019-6706-use-after-free-in-lua-upvaluejoin-function-tc7685575.html>
* <https://www.cve.org/CVERecord?id=CVE-2019-6706>