CVE-2023-43785 | Libx11: out-of-bounds memory access in _xkbreadkeysyms()

A vulnerability was found in libX11 due to a boundary condition within the _XkbReadKeySyms() function. This flaw allows a local user to trigger an out-of-bounds read error and read the contents of memory on the system.

Published: 2023-10-10 Last update: 2025-11-04 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-43785 is rated Moderate Risk (42.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.64%). 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-2023-43785

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 2026-06-15 0.10% 0.64% +0.54%
2 2025-11-21 0.17% 0.10% -0.07%
3 2025-11-18 — 0.17% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-43785

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N 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:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2023-43785

OS Trackers for CVE-2023-43785

vendor priority summary link
alpine — CVE-2023-43785: 1 source package rows (libx11); 9 state rows across 7 repos (3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 2. https://security.alpinelinux.org/vuln/CVE-2023-43785
debian not yet assigned CVE-2023-43785 not yet assigned priority: Debian including 1 source packages (libx11), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2023-43785
gentoo normal CVE-2023-43785: 1 GLSA(s) (202407-21), 1 atom(s) (x11-libs/libX11); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-43785
redhat medium — https://access.redhat.com/security/cve/CVE-2023-43785
suse medium CVE-2023-43785 severity moderate: SUSE including 290 source package names (1.21-5.4:libX11-6-1.6.5-150000.3.33.1, 1.21-5.4:libX11-data-1.6.5-150000.3.33.1, …), 682 product×package rows across 146 product lines (Container bci/openjdk, Container bci/openjdk-devel, … (146 product lines)): Fixed 451, Known Affected 231. https://www.suse.com/security/cve/CVE-2023-43785/
ubuntu medium CVE-2023-43785 medium priority: Ubuntu including 1 source packages (libx11), 8 status rows across 8 suites (bionic, focal, jammy, lunar, mantic, trusty, upstream, xenial): released 8. https://ubuntu.com/security/CVE-2023-43785

Affected software / configurations for CVE-2023-43785

Vendor Product Version Raw CPE
x.org libx11 < 1.8.7 cpe:2.3:a:x.org:libx11:*:*:*:*:*:*:*:*
redhat enterprise_linux 8.0 cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
redhat enterprise_linux 9.0 cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
fedoraproject fedora 38 cpe:2.3:o:fedoraproject:fedora:38:*:*:*:*:*:*:*

References for CVE-2023-43785

cvelogic Threat Intelligence