---
title: "CVE-2017-2624\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-2017-2624?format=md
keywords: index, follow
---

# CVE-2017-2624

Publication date 1 March 2017

Last updated 25 August 2025

---

Ubuntu priority

**Negligible**

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

## Cvss 3 Severity Score

**7.0 · High**

[Score breakdown](https://ubuntu.com/security/CVE-2017-2624?format=md#impact-score)

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## Description

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to
check the received MIT cookie against a series of valid cookies. If the
cookie is correct, it is allowed to attach to the Xorg session. Since most
memcmp() implementations return after an invalid byte is seen, this causes
a time difference between a valid and invalid byte, which could allow an
efficient brute force attack.

[Read the notes from the security team](https://ubuntu.com/security/CVE-2017-2624?format=md#notes)

## Status

Show unmaintained releases

| Package | Ubuntu Release | Status |
| --- | --- | --- |
| xorg-server | 17.04 zesty | Not affected |
| 16.10 yakkety | Ignored end of life |
| 16.04 LTS xenial | Fixed 2:1.18.4-0ubuntu0.3 |
| 14.04 LTS trusty | Fixed 2:1.15.1-0ubuntu2.9 |
| 12.04 LTS precise | Ignored end of life |
| xorg-server-hwe-16.04 | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Fixed 2:1.18.4-1ubuntu6.1~16.04.2 |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Not in release |
| xorg-server-lts-quantal | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Ignored end of life |
| xorg-server-lts-raring | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Ignored end of life |
| xorg-server-lts-saucy | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Ignored end of life |
| xorg-server-lts-trusty | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Ignored end of life |
| xorg-server-lts-utopic | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Not in release |
| xorg-server-lts-vivid | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Not in release |
| xorg-server-lts-wily | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Not in release |
| 12.04 LTS precise | Not in release |
| xorg-server-lts-xenial | 17.04 zesty | Not in release |
| 16.10 yakkety | Not in release |
| 16.04 LTS xenial | Not in release |
| 14.04 LTS trusty | Fixed 2:1.18.3-1ubuntu2.3~trusty2 |
| 12.04 LTS precise | 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-2017-2624?format=md#patch-details)

## Notes

---

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

1.19.0 and lower are affected

### 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 |
| --- | --- |
| xorg-server | * Upstream:   [?id=d7a](https://cgit.freedesktop.org/xorg/xserver/commit/?id=d7ac755f0b618eb1259d93c8a16ec6e39a18627c) * Upstream:   [?id=e9d](https://cgit.freedesktop.org/xorg/xserver/commit/?id=e9dbecf7c259f7e8b610fa93f97ea55f5dafa7af) |

## Severity score breakdown

CVSS version:
CVSS v3.0

**Base score**

7.0 · High

* Base metrics

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

  | Parameter | Value |
  | --- | --- |
  | Base score | 7.0 · High |
  | Exploitability score | - |
  | Impact score | - |

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

## References

* [MITRE](https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-2624)
* [NVD](https://nvd.nist.gov/vuln/detail/CVE-2017-2624)
* [Launchpad](https://launchpad.net/bugs/cve/CVE-2017-2624)
* [Debian](https://security-tracker.debian.org/tracker/CVE-2017-2624)

### Related Ubuntu Security Notices (USN)

+ [USN-3362-1](https://usn.ubuntu.com/USN-3362-1)
+ X.Org X server vulnerabilities
+ 24 July 2017

### Other references

* <https://www.x41-dsec.de/lab/advisories/x41-2017-001-xorg/>
* <http://openwall.com/lists/oss-security/2017/03/01/1>
* <https://www.cve.org/CVERecord?id=CVE-2017-2624>