# CVE-2023-1393: Use after free in xorg-server > A use-after-free flaw in X.Org Server allows local attackers to escalate privileges by destroying a compositor overlay window. - **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:** 30 Mar 2023 - **Updated:** 22 Jan 2026 - **Also known as:** ALSA-2023:1551, ALSA-2023:1592, ALSA-2023:6340, ALSA-2023:6341, ALSA-2023:6916, ALSA-2023:6917, AZL-25859, AZL-35358, AZL-44478, DEBIAN-CVE-2023-1393, DLA-3372-1, DSA-5380-1, GHSA-gvfw-3vr2-x46g, MGASA-2023-0131, OESA-2023-1239, RHSA-2023:1548, RHSA-2023:1549, RHSA-2023:1551, RHSA-2023:1592, RHSA-2023:1594, RHSA-2023:1598, RHSA-2023:1599, RHSA-2023:1600, RHSA-2023:6340, RHSA-2023:6341, RHSA-2023:6916, RHSA-2023:6917, RLSA-2023:1592, SUSE-SU-2023:1674-1, SUSE-SU-2023:1675-1, SUSE-SU-2023:1677-1, SUSE-SU-2023:1678-1, SUSE-SU-2023:1679-1, SUSE-SU-2023:1680-1, SUSE-SU-2023:1716-1, UBUNTU-CVE-2023-1393, USN-5986-1, openSUSE-SU-2024:12827-1, openSUSE-SU-2024:12834-1 ## What is CVE-2023-1393? CVE-2023-1393 is a high-severity use after free vulnerability in Fedoraproject Fedora, published on 30 Mar 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 X.Org Server Overlay Window. A Use-After-Free may lead to local privilege escalation. If a client explicitly destroys the compositor overlay window (aka COW), the Xserver would leave a dangling pointer to that window in the CompScreen structure, which will trigger a use-after-free later. Weakness: CWE-416 (Use After Free) ## Which versions are affected by CVE-2023-1393? It affects 2 products. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `tigervnc` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-icons` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-license` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-selinux` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-server` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-server-minimal` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `tigervnc-server-module` | AlmaLinux:8 | All versions | 1.12.0-9.el8_7.3 | | `xorg-x11-server-Xdmx` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-Xephyr` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-Xnest` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-Xorg` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-Xvfb` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-Xwayland` | AlmaLinux:8 | All versions | 21.1.3-12.el8 | | `xorg-x11-server-common` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-devel` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `xorg-x11-server-source` | AlmaLinux:8 | All versions | 1.20.11-17.el8 | | `tigervnc` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-icons` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-license` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-selinux` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-server` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-server-minimal` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `tigervnc-server-module` | AlmaLinux:9 | All versions | 1.12.0-5.el9_1.2 | | `xorg-x11-server-Xdmx` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-Xephyr` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-Xnest` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-Xorg` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-Xvfb` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-Xwayland` | AlmaLinux:9 | All versions | 22.1.9-2.el9 | | `xorg-x11-server-common` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-devel` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `xorg-x11-server-source` | AlmaLinux:9 | All versions | 1.20.11-19.el9 | | `tigervnc` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-debuginfo` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-icons` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-license` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-server` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-server-applet` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-server-minimal` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | | `tigervnc-server-module` | Red Hat:enterprise_linux:7::client | All versions | 0:1.8.0-25.el7_9 | Products: Fedoraproject Fedora, X.org X Server. ## How do I fix CVE-2023-1393? Apply the vendor's patch. ## Is CVE-2023-1393 being exploited? There is no known exploitation of CVE-2023-1393 in the wild and no public exploit code. ## Other vulnerabilities in Fedoraproject Fedora - [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild) - [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild) - [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild) - [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild) - [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2023-1393 and fix it if it is affected. What it is: CVE-2023-1393 is a high-severity use after free vulnerability in Fedoraproject Fedora, published on 30 Mar 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-2023-1393 in the wild and no public exploit code. Affected product: Fedoraproject Fedora. 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-2023-1393/ (Markdown: https://insights.sbomify.com/CVE-2023-1393/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2023-1393 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-1393 - OSV: https://osv.dev/vulnerability/CVE-2023-1393 --- From sbomify Insights: https://insights.sbomify.com/CVE-2023-1393/ Summaries are generated and may contain mistakes; the official description above is the record.