CVE-2023-6377 | Xorg-x11-server: out-of-bounds memory reads/writes in xkb button actions

A flaw was found in xorg-server. Querying or changing XKB button actions such as moving from a touchpad to a mouse can result in out-of-bounds memory reads and writes. This may allow local privilege escalation or possible remote code execution in cases where X11 forwarding is involved.

Published: 2023-12-13 Last update: 2026-03-24 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2023-6377 is rated Moderate Risk (51.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 0.36%). Mandatory action: Review affected assets and schedule remediation.

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-2023-6377

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 2025-09-02 0.33% 0.36% +0.03%
2 2025-08-30 0.41% 0.33% -0.08%
3 2025-05-03 0.41%

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-6377

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.8 5.9 [email protected]
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
1.8 5.9 [email protected]

Weakness enumeration for CVE-2023-6377

OS Trackers for CVE-2023-6377

vendor priority summary link
alpine CVE-2023-6377: 1 source package rows (xorg-server); 5 state rows across 5 repos (3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 5, open 0. https://security.alpinelinux.org/vuln/CVE-2023-6377
debian not yet assigned CVE-2023-6377 not yet assigned priority: Debian including 2 source packages (xorg-server, xwayland), 9 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 8, open 1. https://security-tracker.debian.org/tracker/CVE-2023-6377
gentoo normal CVE-2023-6377: 1 GLSA(s) (202401-30), 2 atom(s) (x11-base/xorg-server, x11-base/xwayland); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-6377
redhat high https://access.redhat.com/security/cve/CVE-2023-6377
suse high https://www.suse.com/security/cve/CVE-2023-6377/
ubuntu medium CVE-2023-6377 medium priority: Ubuntu including 11 source packages (xorg, xorg-hwe-16.04, …), 132 status rows across 12 suites (bionic, focal, jammy, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 84, not-affected 19, released 15, needs-triage 9, ignored 5. https://ubuntu.com/security/CVE-2023-6377

Affected software / configurations for CVE-2023-6377

Vendor Product Version Raw CPE
redhat enterprise_linux_eus 9.2 cpe:2.3:o:redhat:enterprise_linux_eus:9.2:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
debian debian_linux 12.0 cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:*
x.org x_server < 21.1.10 cpe:2.3:a:x.org:x_server:*:*:*:*:*:*:*:*
x.org xwayland < 23.2.3 cpe:2.3:a:x.org:xwayland:*:*:*:*:*:*:*:*
tigervnc tigervnc cpe:2.3:a:tigervnc:tigervnc:-:*:*:*:*:*:*:*

References for CVE-2023-6377

URL Tags
https://access.redhat.com/errata/RHSA-2023:7886 Vendor Advisory
https://access.redhat.com/errata/RHSA-2024:0006
https://access.redhat.com/errata/RHSA-2024:0009
https://access.redhat.com/errata/RHSA-2024:0010
https://access.redhat.com/errata/RHSA-2024:0014
https://access.redhat.com/errata/RHSA-2024:0015
https://access.redhat.com/errata/RHSA-2024:0016
https://access.redhat.com/errata/RHSA-2024:0017
https://access.redhat.com/errata/RHSA-2024:0018
https://access.redhat.com/errata/RHSA-2024:0020
https://access.redhat.com/errata/RHSA-2024:2169
https://access.redhat.com/errata/RHSA-2024:2170
https://access.redhat.com/errata/RHSA-2024:2995
https://access.redhat.com/errata/RHSA-2024:2996
https://access.redhat.com/errata/RHSA-2025:13998
https://access.redhat.com/security/cve/CVE-2023-6377 Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2253291 Issue Tracking
https://gitlab.freedesktop.org/xorg/xserver/-/commit/0c1a93d319558fe3ab2d94f51d174b4f93810afd Patch
https://lists.x.org/archives/xorg-announce/2023-December/003435.html Mailing List
http://www.openwall.com/lists/oss-security/2023/12/13/1
https://lists.debian.org/debian-lts-announce/2023/12/msg00008.html
https://lists.debian.org/debian-lts-announce/2023/12/msg00013.html
https://lists.fedoraproject.org/archives/list/[email protected]/message/6R63Z6GIWM3YUNZRCGFODUXLW3GY2HD6/
https://lists.fedoraproject.org/archives/list/[email protected]/message/7PP47YXKM5ETLCYEF6473R3VFCJ6QT2S/
https://lists.fedoraproject.org/archives/list/[email protected]/message/IFHV5KCQ2SVOD4QMCPZ5HC6YL44L7YJD/
https://lists.fedoraproject.org/archives/list/[email protected]/message/LJDFWDB7EQVZA45XDP7L5WRSRWS6RVRR/
https://security.gentoo.org/glsa/202401-30
https://security.netapp.com/advisory/ntap-20240125-0003/
https://www.debian.org/security/2023/dsa-5576
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