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CVE-2018-15857

25
FAUCET Score

CVE-2018-15857 describes an invalid free vulnerability in xkbcommon versions prior to 0.8.1, specifically within the ExprAppendMultiKeysymList function. This flaw allows local attackers to crash xkbcommon keymap parsers or potentially achieve other unspecified impacts by providing a specially crafted keymap file. Rated with a CVSS score of 7.8 (HIGH), this vulnerability has a low attack complexity and requires local user privileges, but can lead to high impacts on confidentiality, integrity, and availability. The EPSS score is very low, indicating a minimal likelihood of exploitation in the wild. There is no evidence of active exploitation, nor are there any public exploit modules available in Metasploit, Nuclei, or ExploitDB. Furthermore, the CVE has received no community discussion or media coverage, suggesting a low level of public awareness or concern.

Impacted Technologies

VendorProductVersion(s)CPE
< 0.8.1CPE matchmatch criteria
cpe:2.3:a:xkbcommon:libxkbcommon:*:*:*:*:*:*:*:*
< 0.8.1CPE matchmatch criteria
cpe:2.3:a:xkbcommon:xkbcommon:*:*:*:*:*:*:*:*
14.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:14.04:*:*:*:lts:*:*:*
16.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
18.04CPE matchmatch criteria
cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*

CVSS Data

CVSS version used by this source: 3.0

7.8HIGH

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
0.45%
Probability of exploitation in next 30 days
EPSS Percentile
36.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-25
Model: v2026.06.15
This CVE's current EPSS score of 0.0045 is in the 77th percentile among its peer group of 16,985 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (9)

github_advisorypatch availablevia nvd_reference
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: gdm-1:3.28.2-16.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libX11-0:1.6.7-2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: libxkbcommon-0:0.7.1-3.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: mesa-libGLw-0:8.0.0-5.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: xorg-x11-drv-ati-0:19.0.1-2.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: xorg-x11-drv-vesa-0:2.4.0-3.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: xorg-x11-drv-wacom-0:0.36.1-3.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: xorg-x11-server-0:1.20.4-7.el7
View patch

Vendor Advisories (1)

redhatCVE-2018-15857Moderate

libxkbcommon: Invalid free in ExprAppendMultiKeysymList resulting in a crash

Jul 30, 2018

References

access.redhat.com / errata/RHSA-2019:2079
github.com / xkbcommon/libxkbcommon/commit/c1e5ac16e77a21f87bdf3bc4dea61b037a17dddb
PatchThird Party Advisory
lists.freedesktop.org / archives/wayland-devel/2018-August/039232.html
Mailing ListPatchThird Party Advisory
security.gentoo.org / glsa/201810-05
Third Party Advisory
usn.ubuntu.com / 3786-1
Third Party Advisory
usn.ubuntu.com / 3786-2
Third Party Advisory