# CVE-2023-6377: Xorg-x11-server: out-of-bounds memory reads/writes in xkb button actions > Out-of-bounds memory access in Xorg X11 server allows local privilege escalation or remote code execution via X11 forwarding. - **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 13 Dec 2023 - **Updated:** 23 Jun 2026 - **Also known as:** AZL-32179, AZL-44700, BELL-CVE-2023-6377, CLSA-2025-1763558418, DEBIAN-CVE-2023-6377, DLA-3686-2, DSA-5576-2, GHSA-xp6x-8hgv-x5w5, RHSA-2025:13998, SUSE-SU-2023:4925-1, SUSE-SU-2023:4926-1, SUSE-SU-2023:4933-1, SUSE-SU-2023:4934-1, SUSE-SU-2023:4935-1, SUSE-SU-2023:4949-1, UBUNTU-CVE-2023-6377 ## What is CVE-2023-6377? CVE-2023-6377 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 13 Dec 2023. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description 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. Weakness: CWE-125 (Out-of-bounds Read) ## Which versions are affected by CVE-2023-6377? It affects 5 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `tigervnc` | Red Hat:rhel_els:6 | All versions | 0:1.1.0-25.el6_10.14 | | `tigervnc-debuginfo` | Red Hat:rhel_els:6 | All versions | 0:1.1.0-25.el6_10.14 | | `tigervnc-server` | Red Hat:rhel_els:6 | All versions | 0:1.1.0-25.el6_10.14 | | `tigervnc-server-applet` | Red Hat:rhel_els:6 | All versions | 0:1.1.0-25.el6_10.14 | | `tigervnc-server-module` | Red Hat:rhel_els:6 | All versions | 0:1.1.0-25.el6_10.14 | | `xorg-x11-server` | SUSE:Enterprise Storage 7.1 | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise High Performance Computing 15 SP2-LTSS | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise High Performance Computing 15 SP3-ESPOS | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise High Performance Computing 15 SP3-LTSS | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Module for Basesystem 15 SP4 | All versions | 1.20.3-150400.38.35.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Module for Basesystem 15 SP5 | All versions | 21.1.4-150500.7.13.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Module for Development Tools 15 SP4 | All versions | 1.20.3-150400.38.35.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Module for Development Tools 15 SP5 | All versions | 21.1.4-150500.7.13.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server 12 SP5 | All versions | 1.19.6-10.62.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server 15 SP2-LTSS | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server 15 SP3-LTSS | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server for SAP Applications 12 SP5 | All versions | 1.19.6-10.62.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server for SAP Applications 15 SP2 | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Server for SAP Applications 15 SP3 | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Software Development Kit 12 SP5 | All versions | 1.19.6-10.62.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Workstation Extension 15 SP4 | All versions | 1.20.3-150200.22.5.85.1 | | `xwayland` | SUSE:Linux Enterprise Workstation Extension 15 SP4 | All versions | 21.1.4-150400.3.26.1 | | `xorg-x11-server` | SUSE:Linux Enterprise Workstation Extension 15 SP5 | All versions | 1.20.3-150200.22.5.85.1 | | `xwayland` | SUSE:Linux Enterprise Workstation Extension 15 SP5 | All versions | 22.1.5-150500.7.11.1 | | `xorg-x11-server` | openSUSE:Leap 15.4 | All versions | 1.20.3-150200.22.5.85.1 | | `xorg-x11-server` | openSUSE:Leap 15.4 | All versions | 1.20.3-150400.38.35.1 | | `xwayland` | openSUSE:Leap 15.4 | All versions | 21.1.4-150400.3.26.1 | | `xorg-x11-server` | openSUSE:Leap 15.5 | All versions | 21.1.4-150500.7.13.1 | | `xwayland` | openSUSE:Leap 15.5 | All versions | 22.1.5-150500.7.11.1 | Products: Debian Debian Linux, Redhat Enterprise Linux Eus, Tigervnc Tigervnc, X.org X Server, X.org Xwayland. ## How do I fix CVE-2023-6377? Apply the vendor's patch. ## Is CVE-2023-6377 being exploited? There is no known exploitation of CVE-2023-6377 in the wild and no public exploit code. ## Other vulnerabilities in Debian Debian Linux - [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild) - [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild) - [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild) - [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild) - [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-6377 and fix it if it is affected. What it is: CVE-2023-6377 is a high-severity memory corruption vulnerability in Debian Debian Linux, published on 13 Dec 2023. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2023-6377 in the wild and no public exploit code. Affected product: Debian Debian Linux. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2023-6377/ (Markdown: https://insights.sbomify.com/CVE-2023-6377/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-6377 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-6377 - OSV: https://osv.dev/vulnerability/CVE-2023-6377 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-6377/ Summaries are generated and may contain mistakes; the official description above is the record.