CVE-2018-15863

Unchecked NULL pointer usage in ResolveStateAndPredicate in xkbcomp/compat.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 with a no-op modmask expression.

Published: 2018-08-25 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-15863 is rated Low Risk (29.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.07%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-15863

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-03 0.04% 0.07% +0.03%
2 2025-11-21 0.06% 0.04% -0.01%
3 2025-11-18 — 0.06% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-15863

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.0 MEDIUM
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]
2.1 2.0 LOW
AV:L/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 2.9 [email protected]

Weakness enumeration for CVE-2018-15863

OS Trackers for CVE-2018-15863

vendor priority summary link
alpine medium CVE-2018-15863: 1 source package rows (xkbcomp); 6 state rows across 6 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, 3.23-main, edge-main); fixed 6, open 0. https://security.alpinelinux.org/vuln/CVE-2018-15863
debian low CVE-2018-15863 low priority: Debian including 2 source packages (libxkbcommon, x11-xkb-utils), 10 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5, resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-15863
gentoo normal CVE-2018-15863: 1 GLSA(s) (201810-05), 1 atom(s) (x11-libs/libxkbcommon); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-15863
redhat low — https://access.redhat.com/security/cve/CVE-2018-15863
suse low CVE-2018-15863 severity low: SUSE including 342 source package names (0.38.1.5.8.45:libxkbcommon0-0.8.2-3.3.1, 0.38.1:libxkbcommon0-0.8.2-3.3.1, …), 623 product×package rows across 175 product lines (Container suse/sl-micro/6.0/base-os-container, Container suse/sl-micro/6.0/toolbox, … (175 product lines)): Fixed 365, Known Affected 231, Known Not Affected 25, First Fixed 2. https://www.suse.com/security/cve/CVE-2018-15863/
ubuntu medium CVE-2018-15863 medium priority: Ubuntu including 1 source packages (libxkbcommon), 5 status rows across 5 suites (bionic, cosmic, trusty, upstream, xenial): released 4, not-affected 1. https://ubuntu.com/security/CVE-2018-15863

Affected software / configurations for CVE-2018-15863

Vendor Product Version Raw CPE
xkbcommon libxkbcommon <= 0.8.1 cpe:2.3:a:xkbcommon:libxkbcommon:*:*:*:*:*:*:*:*
xkbcommon xkbcommon <= 0.8.1 cpe:2.3:a:xkbcommon:xkbcommon:*:*:*:*:*:*:*:*
canonical ubuntu_linux 14.04 cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

References for CVE-2018-15863

cvelogic Threat Intelligence