What is CVE-2018-15858?

CVE-2018-15858 is a medium-severity vulnerability in Xkbcommon Libxkbcommon, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2018-08-25.

How severe is CVE-2018-15858?

Medium severity. CVSS v3 base score is 5.5 out of 10.

NULL pointer dereference in Xkbcommon Libxkbcommon

CVE-2018-15858

Unchecked NULL pointer usage when handling invalid aliases in CopyKeyAliasesToKeymap in xkbcomp/keycodes.c in xkbcommon before 0.8.1 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file.

Published 2018-08-25 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.5 (Medium). Vector: CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.004 (34.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 35th percentile — 34.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000

Affected products

Xkbcommon Libxkbcommon
Xkbcommon
Canonical Ubuntu Linux — versions 14.04, 16.04, 18.04

Weakness classification (CWE)

CWE-476 — NULL Pointer Dereference

References

github.com/xkbcommon/libxkbcommon/commit/badb428e63387140720f22486b3acbd3d73885… (Patch, Third Party Advisory)
security.gentoo.org/glsa/201810-05 (vendor-advisory, Third Party Advisory)
usn.ubuntu.com/3786-1/ (vendor-advisory, Third Party Advisory)
usn.ubuntu.com/3786-2/ (vendor-advisory, Third Party Advisory)
lists.freedesktop.org/archives/wayland-devel/2018-August/039232.html (Patch, Mailing List, Third Party Advisory)

Frequently asked questions

What is CVE-2018-15858?: CVE-2018-15858 is a medium-severity vulnerability in Xkbcommon Libxkbcommon, classified under NULL Pointer Dereference. CVSS score: 5.5/10. Published 2018-08-25.
How severe is CVE-2018-15858?: Medium severity. CVSS v3 base score is 5.5 out of 10.