CVE-2018-15856

Severity: medium (CVSS 5.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-08-25 · updated 2026-06-17
Weakness: CWE-835

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.

Affected products

Canonical Ubuntu Linux: 14.04, 16.04, 18.04
Xkbcommon: before 0.8.1 — fixed in 0.8.1

How to fix

Upgrade to a fixed version: Xkbcommon 0.8.1. Check the vendor advisory for mitigations.

References

https://access.redhat.com/errata/RHSA-2019:2079
https://github.com/xkbcommon/libxkbcommon/commit/842e4351c2c97de6051cab6ce36b4a81e709a0e1
https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
https://security.gentoo.org/glsa/201810-05
https://usn.ubuntu.com/3786-1/
https://usn.ubuntu.com/3786-2/
https://access.redhat.com/errata/RHSA-2019:2079
https://github.com/xkbcommon/libxkbcommon/commit/842e4351c2c97de6051cab6ce36b4a81e709a0e1
https://lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html
https://security.gentoo.org/glsa/201810-05
https://usn.ubuntu.com/3786-1/
https://usn.ubuntu.com/3786-2/

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