---
title: "CVE-2016-2338\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-2016-2338?format=md
keywords: index, follow
---

# CVE-2016-2338

Publication date 29 September 2022

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-2016-2338?format=md#impact-score)

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## Description

An exploitable heap overflow vulnerability exists in the Psych::Emitter
start\_document function of Ruby. In Psych::Emitter start\_document function
heap buffer "head" allocation is made based on tags array length. Specially
constructed object passed as element of tags array can increase this array
size after mentioned allocation and cause heap overflow.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| ruby-psych | 19.10 eoan | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| ruby1.9.1 | 19.10 eoan | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| ruby2.0 | 19.10 eoan | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| ruby2.3 | 19.10 eoan | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Not affected |
| 14.04 LTS trusty | Not in release |
| ruby2.5 | 19.10 eoan | Not affected |
| 18.04 LTS bionic | Not affected |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| ruby2.7 | 19.10 eoan | Not in release |
| 18.04 LTS bionic | Not in release |
| 16.04 LTS xenial | Not in release |
| 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-2016-2338?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 |
| --- | --- |
| ruby2.3 | * Upstream:   [?id=db4](https://git.ruby-lang.org/ruby.git/commit/?id=db48c307944a9a18877236bdf9e9b778875f38ed) |
| ruby2.5 | * Upstream:   [?id=db4](https://git.ruby-lang.org/ruby.git/commit/?id=db48c307944a9a18877236bdf9e9b778875f38ed) |

## 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-2016-2338)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-2338)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-2338)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-2338)

### Other references

* <http://www.talosintelligence.com/reports/TALOS-2016-0032/>
* <https://www.cve.org/CVERecord?id=CVE-2016-2338>