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Fencer Vulns
medium 5.5

CVE-2018-15859 json

Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by loca…

published 2018-08-25 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-7716

cvss
5.5
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 45%
public exploits
0
none known

Summary

Unchecked NULL pointer usage when parsing invalid atoms in ExprResolveLhs in xkbcomp/expr.c in xkbcommon before 0.8.2 could be used by local attackers to crash (NULL pointer dereference) the xkbcommon parser by supplying a crafted keymap file, because lookup failures are mishandled.

Patch / fix

  • libxkbcommon Debian 14, Debian 13, Debian 12 0.8.2-1

debian advisories DEBIAN-CVE-2018-15859

  • libxkbcommon Ubuntu 14.04 LTS 0.4.1-0ubuntu1.1
  • libxkbcommon Ubuntu 16.04 LTS 0.5.0-1ubuntu2.1
  • libxkbcommon Ubuntu 18.04 LTS 0.8.0-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2018-15859

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • gdm RHEL 7 1:3.28.2-16.el7
  • libX11 RHEL 7 1.6.7-2.el7
  • mesa-libGLw RHEL 7 8.0.0-5.el7
  • libxkbcommon RHEL 7 0.7.1-3.el7
  • libX11-common RHEL 7 1.6.7-2.el7
  • xorg-x11-server RHEL 7 1.20.4-7.el7
  • libxkbcommon-x11 RHEL 7 0.7.1-3.el7
  • xorg-x11-drv-ati RHEL 7 19.0.1-2.el7

red hat advisories RHSA-2019:2079

  • xkbcomp SLES for SAP applications 16.0, SLES 16.0 1.4.7-160000.3.1
  • xkbcomp SLE Module for Basesystem 15 SP7, SLE Module for Basesystem 15 SP6, openSUSE Leap 15.6 1.4.1-150000.3.6.1
  • libxkbcommon SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 0.6.1-9.3.1
  • libxkbcommon SLE Module for Basesystem 15 0.8.2-3.3.1
  • xkbcomp SLES LTSS Extended Security 12 SP5 1.2.4-11.3.1

suse advisories SUSE-SU-2026:20186-1SUSE-SU-2025:4426-1SUSE-SU-2025:4407-1SUSE-SU-2024:0037-1SUSE-SU-2018:3685-1

  • xkbcomp openSUSE Leap 16.0 1.4.7-160000.3.1
  • xkbcomp openSUSE Tumbleweed 1.5.0-1.1

opensuse advisories openSUSE-SU-2026:20123-1openSUSE-SU-2025:15815-1

  • xkbcomp Alpine 3.24, Alpine 3.23, Alpine 3.22 +4 more 1.5.0-r0

alpine advisories ALPINE-CVE-2018-15859

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-15859 updated cvss 3.3

libxkbcommon: xkbcomp: NULL pointer dereference when parsing invalid atoms in ExprResolveLhs resulting in a crash

  • Red Hat Enterprise Linux 9 xkbcomp Red Hat Enterprise Linux 10 xkbcomp
    affected: no fix available “Fix deferred”
  • Red Hat Enterprise Linux Client (v. 7) gdm 3.28.2-16.el7, libX11 1.6.7-2.el7, libxkbcommon 0.7.1-3.el7, libX11-common 1.6.7-2.el7, libxkbcommon-x11 0.7.1-3.el7, xorg-x11-server 1.20.4-7.el7, +6 more Red Hat Enterprise Linux Client Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-7.el7, xorg-x11-server-Xvfb 1.20.4-7.el7, xorg-x11-server-Xnest 1.20.4-7.el7, xorg-x11-server-source 1.20.4-7.el7, xorg-x11-server-Xwayland 1.20.4-7.el7 Red Hat Enterprise Linux ComputeNode (v. 7) libX11 1.6.7-2.el7, libxkbcommon 0.7.1-3.el7, libX11-common 1.6.7-2.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) gdm 3.28.2-16.el7, libxkbcommon-x11 0.7.1-3.el7, xorg-x11-server 1.20.4-7.el7, xorg-x11-drv-wacom 0.36.1-3.el7, xorg-x11-server-Xdmx 1.20.4-7.el7, xorg-x11-server-Xorg 1.20.4-7.el7, +6 more Red Hat Enterprise Linux Server (v. 7) gdm 3.28.2-16.el7, libX11 1.6.7-2.el7, mesa-libGLw 8.0.0-5.el7, libxkbcommon 0.7.1-3.el7, libX11-common 1.6.7-2.el7, libxkbcommon-x11 0.7.1-3.el7, +7 more Red Hat Enterprise Linux Server Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-7.el7, xorg-x11-server-Xvfb 1.20.4-7.el7, xorg-x11-server-Xnest 1.20.4-7.el7, xorg-x11-server-source 1.20.4-7.el7, xorg-x11-server-Xwayland 1.20.4-7.el7
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 7) gdm 3.28.2-16.el7, libX11 1.6.7-2.el7, mesa-libGLw 8.0.0-5.el7, libxkbcommon 0.7.1-3.el7, libX11-common 1.6.7-2.el7, libxkbcommon-x11 0.7.1-3.el7, +7 more Red Hat Enterprise Linux Workstation Optional (v. 7) xorg-x11-server-Xdmx 1.20.4-7.el7, xorg-x11-server-Xvfb 1.20.4-7.el7, xorg-x11-server-Xnest 1.20.4-7.el7, xorg-x11-server-source 1.20.4-7.el7, xorg-x11-server-Xwayland 1.20.4-7.el7
    fixed: vendor fix RHSA-2019:2079
  • Red Hat Enterprise Linux 8 libxkbcommon, libxkbcommon-x11
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.53% chance of exploitation in the next 30 days, higher than 45% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.0 5.5 CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 2.1 AV:L/AC:L/Au:N/C:N/I:N/A:P

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.