---
title: "CVE-2015-7978\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-2015-7978?format=md
keywords: index, follow
---

# CVE-2015-7978

Publication date 31 December 2015

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-2015-7978?format=md#impact-score)

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## Description

NTP before 4.2.8p6 and 4.3.0 before 4.3.90 allows a remote attackers to
cause a denial of service (stack exhaustion) via an ntpdc relist command,
which triggers recursive traversal of the restriction list.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2015-7978?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| ntp | 17.04 zesty | Not affected |
| 16.10 yakkety | Not affected |
| 16.04 LTS xenial | Fixed 1:4.2.8p4+dfsg-3ubuntu5.3 |
| 15.10 wily | Ignored end of life |
| 15.04 vivid | Ignored end of life |
| 14.04 LTS trusty | Fixed 1:4.2.6.p5+dfsg-3ubuntu2.14.04.10 |
| 12.04 LTS precise | Fixed 1:4.2.6.p3+dfsg-1ubuntu3.11 |

---

* [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-2015-7978?format=md#patch-details)

## Notes

---

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

same patch as CVE-2015-7977

### 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 |
| --- | --- |
| ntp | * Upstream:   [8a0c765](https://github.com/ntp-project/ntp/commit/8a0c765f3c47633fa262356b0818788d1cf249b1) |

## 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:3.0/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-2015-7978)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2015-7978)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2015-7978)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2015-7978)

### Related Ubuntu Security Notices (USN)

+ [USN-3096-1](https://usn.ubuntu.com/USN-3096-1)
+ NTP vulnerabilities
+ 5 October 2016

### Other references

* <http://support.ntp.org/bin/view/Main/SecurityNotice#January_2016_NTP_4_2_8p6_Securit>
* <http://www.talosintel.com/reports/TALOS-2016-0075/>
* <https://www.cve.org/CVERecord?id=CVE-2015-7978>