---
title: "CVE-2016-9963\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-2016-9963?format=md
keywords: index, follow
---

# CVE-2016-9963

Publication date 16 December 2016

Last updated 25 August 2025

---

Ubuntu priority

**Medium**

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

## Cvss 3 Severity Score

**5.9 · Medium**

[Score breakdown](https://ubuntu.com/security/CVE-2016-9963?format=md#impact-score)

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## Description

Exim before 4.87.1 might allow remote attackers to obtain the private DKIM
signing key via vectors related to log files and bounce messages.

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| exim4 | 16.10 yakkety | Fixed 4.87-3ubuntu1.1 |
| 16.04 LTS xenial | Fixed 4.86.2-2ubuntu2.1 |
| 14.04 LTS trusty | Fixed 4.82-3ubuntu2.2 |
| 12.04 LTS precise | Fixed 4.76-3ubuntu3.4 |

---

* [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-2016-9963?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 |
| --- | --- |
| exim4 | * Upstream:   [87cb4a1](https://github.com/Exim/exim/commit/87cb4a166c47b57df48c2918e47801d77639fbb0) * Upstream:   [46672dc](https://github.com/Exim/exim/commit/46672dc8be913fb02f0aa822d79c590fac276182) * Upstream:   [fd3961f](https://github.com/Exim/exim/commit/fd3961f062107c5c64016cff0331fd2cf1181cdd) * Upstream:   [be2b8e5](https://github.com/Exim/exim/commit/be2b8e517f4946d2ad0cb0100e7b078cb4d9b65f) * Upstream:   [31c02de](https://github.com/Exim/exim/commit/31c02defdc5118834e801d4fe8f11c1d9b5ebadf) * Upstream:   [f915863](https://github.com/Exim/exim/commit/f915863397aa037a437155da67424d094821a23b) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

5.9 · Medium

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 5.9 · Medium |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-9963)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2016-9963)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2016-9963)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2016-9963)

### Related Ubuntu Security Notices (USN)

+ [USN-3164-1](https://usn.ubuntu.com/USN-3164-1)
+ Exim vulnerability
+ 5 January 2017

### Other references

* <http://www.openwall.com/lists/oss-security/2016/12/16/1>
* <https://www.exim.org/static/doc/CVE-2016-9963.txt>
* <https://www.cve.org/CVERecord?id=CVE-2016-9963>