CVE-2018-15856

Publication date 25 August 2018

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An infinite loop when reaching EOL unexpectedly in compose/parser.c (aka the keymap parser) in xkbcommon before 0.8.1 could be used by local attackers to cause a denial of service during parsing of crafted keymap files.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
libxkbcommon	18.10 cosmic	Not affected
	18.04 LTS bionic	Fixed 0.8.0-1ubuntu0.1
	16.04 LTS xenial	Fixed 0.5.0-1ubuntu2.1
	14.04 LTS trusty	Fixed 0.4.1-0ubuntu1.1

Notes

leosilva

Trusty need to be researched since code is quite different and /compose is not present.

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
libxkbcommon	Vendor: 842e435

Severity score breakdown

CVSS version: CVSS v3.0

Base score 5.5 · Medium

Base metrics

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

Scores

Parameter	Value
Base score	5.5 · Medium
Exploitability score	-
Impact score	-

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

References

Related Ubuntu Security Notices (USN)

USN-3786-1
libxkbcommon vulnerabilities
8 October 2018

USN-3786-2
libxkbcommon vulnerabilities
6 November 2018