---
title: "CVE-2016-2851\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-2016-2851?format=md
keywords: index, follow
---

# CVE-2016-2851

Publication date 9 March 2016

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-2016-2851?format=md#impact-score)

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## Description

Integer overflow in proto.c in libotr before 4.1.1 on 64-bit platforms
allows remote attackers to cause a denial of service (memory corruption and
application crash) or execute arbitrary code via a series of large OTR
messages, which triggers a heap-based buffer overflow.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| libotr | 15.10 wily | Fixed 4.1.0-2ubuntu0.1 |
| 14.04 LTS trusty | Fixed 4.0.0-2.2ubuntu1.1 |
| 12.04 LTS precise | Fixed 3.2.0-4ubuntu0.3 |

---

* [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-2016-2851)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-2851)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-2851)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-2851)

### Related Ubuntu Security Notices (USN)

+ [USN-2926-1](https://usn.ubuntu.com/USN-2926-1)
+ OTR vulnerability
+ 10 March 2016

### Other references

* <https://lists.cypherpunks.ca/pipermail/otr-users/2016-March/002581.html>
* <https://www.x41-dsec.de/lab/advisories/x41-2016-001-libotr/>
* <https://www.cve.org/CVERecord?id=CVE-2016-2851>