Cyber Resilience

CVE-2023-6377

Memory Safety in Debian Linux 10.0 … 12.0

Published
13 December 2023
Modified
23 June 2026
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.016 73th percentile
Risk Priority 73 floored blend · peak EPSS

Summary

CVE-2023-6377 is a high-severity Out-of-bounds Read (CWE-125) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 27% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2023-6377 is an out-of-bounds memory access flaw in the xorg-server X11 implementation. The issue occurs when querying or modifying XKB button actions, such as during input device transitions between a touchpad and a mouse, and is tracked under CWE-125. It affects the core X server component used in most Linux graphical environments.

A local attacker with a valid X session can trigger the flaw to perform arbitrary reads and writes in the X server process, enabling local privilege escalation to root. When X11 forwarding is enabled over SSH or similar tunnels, the same primitive may be reachable remotely and can lead to code execution on the forwarded display server.

Red Hat has published multiple errata (RHSA-2023:7886 and the 2024:0006/0009/0010/0014 family) that deliver patched xorg-server packages for affected Enterprise Linux distributions; applying these updates is the primary mitigation.

EPSS for the CVE rose sharply from a low baseline to a peak of 0.3221 on 2025-01-22 before receding, indicating that meaningful exploitation interest developed well after the original disclosure.

EU & UK References

Vulnerability Data

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…

more

in cases where X11 forwarding is involved.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1211 Exploitation for Stealth Stealth
Adversaries may exploit vulnerabilities to evade detection by hiding activity, suppressing logging, or operating within trusted or unmonitored components.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-6478Same product: Debian Debian Linux
CVE-2026-50262Same product: Redhat Enterprise Linux
CVE-2026-34000Same product: Redhat Enterprise Linux
CVE-2025-26595Same product: Redhat Enterprise Linux
CVE-2025-26598Same product: Redhat Enterprise Linux
CVE-2025-26599Same product: Redhat Enterprise Linux
CVE-2025-26596Same product: Redhat Enterprise Linux
CVE-2025-26601Same product: Redhat Enterprise Linux
CVE-2025-26594Same product: Redhat Enterprise Linux
CVE-2025-26600Same product: Redhat Enterprise Linux

Affected Assets

redhat
enterprise linux eus
9.2
debian
debian linux
10.0, 11.0, 12.0
x.org
x server
≤ 21.1.10
x.org
xwayland
≤ 23.2.3
tigervnc
tigervnc
all versions

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure-development practices such as bounds checking and memory-safe languages directly prevent out-of-bounds reads.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover instances of out-of-bounds reads after code is deployed.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing out-of-bounds read flaws.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance includes fuzzing and static analysis that detect out-of-bounds read defects before release.

A.8.15 Logging partial match
finds

Logging can record evidence of an out-of-bounds read but does not prevent the weakness itself.

prevents

Secure development life cycle mandates input validation and bounds checking that directly prevent out-of-bounds reads.

prevents

Application security requirements include explicit bounds and memory-safety specifications that mitigate buffer over-reads.

prevents

Secure system architecture and engineering principles require memory-safe design patterns and runtime protections against out-of-bounds access.

prevents

Secure coding standards explicitly forbid unsafe pointer arithmetic and mandate bounds-checked reads, eliminating CWE-125.

References