{"id":"CVE-2023-6816","title":"Xorg-x11-server: heap buffer overflow in devicefocusevent and procxiquerypointer","summary":"A flaw was found in X.Org server. Both DeviceFocusEvent and the XIQueryPointer reply contain a bit for each logical button currently down. Buttons can be arbitrarily mapped to any value up to 255, but the X.Org Server was only allocating…","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-787"],"vendor":"Red Hat","product":"tigervnc","affected":["tigervnc (all versions)","xorg-x11-server (all versions)","tigervnc (all versions)","tigervnc (all versions)","xorg-x11-server (all versions)","xorg-x11-server-Xwayland (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","tigervnc (all versions)","xorg-x11-server (all versions)","xorg-x11-server-Xwayland (all versions)","tigervnc (all versions)","tigervnc (all versions)","xorg-x11-server"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2024-01-18T14:05:47.630340Z"},"published":"2024-01-18","updated":"2026-11-04","sourceUpdated":"2026-11-04T21:07:07.769Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-6816","references":[{"url":"https://access.redhat.com/errata/RHSA-2024:0320","label":"RHSA-2024:0320"},{"url":"https://access.redhat.com/errata/RHSA-2024:0557","label":"RHSA-2024:0557"},{"url":"https://access.redhat.com/errata/RHSA-2024:0558","label":"RHSA-2024:0558"},{"url":"https://access.redhat.com/errata/RHSA-2024:0597","label":"RHSA-2024:0597"},{"url":"https://access.redhat.com/errata/RHSA-2024:0607","label":"RHSA-2024:0607"},{"url":"https://access.redhat.com/errata/RHSA-2024:0614","label":"RHSA-2024:0614"},{"url":"https://access.redhat.com/errata/RHSA-2024:0617","label":"RHSA-2024:0617"},{"url":"https://access.redhat.com/errata/RHSA-2024:0621","label":"RHSA-2024:0621"},{"url":"https://access.redhat.com/errata/RHSA-2024:0626","label":"RHSA-2024:0626"},{"url":"https://access.redhat.com/errata/RHSA-2024:0629","label":"RHSA-2024:0629"},{"url":"https://access.redhat.com/errata/RHSA-2024:2169","label":"RHSA-2024:2169"},{"url":"https://access.redhat.com/errata/RHSA-2024:2170","label":"RHSA-2024:2170"},{"url":"https://access.redhat.com/errata/RHSA-2024:2995","label":"RHSA-2024:2995"},{"url":"https://access.redhat.com/errata/RHSA-2024:2996","label":"RHSA-2024:2996"},{"url":"https://access.redhat.com/errata/RHSA-2025:12751","label":"RHSA-2025:12751"},{"url":"https://access.redhat.com/security/cve/CVE-2023-6816"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2257691","label":"RHBZ#2257691"}],"tags":["cve.org"],"epss":0.02106,"epssPercentile":0.81807,"ingestedAt":"2026-11-05T21:36:00.595Z","slug":"CVE-2023-6816","body":"## Overview\n\nA flaw was found in X.Org server. Both DeviceFocusEvent and the XIQueryPointer reply contain a bit for each logical button currently down. Buttons can be arbitrarily mapped to any value up to 255, but the X.Org Server was only allocating space for the device's particular number of buttons, leading to a heap overflow if a bigger value was used.\n\n## Affected\n\n- `tigervnc (all versions)`\n- `xorg-x11-server (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `xorg-x11-server (all versions)`\n- `xorg-x11-server-Xwayland (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `xorg-x11-server (all versions)`\n- `xorg-x11-server-Xwayland (all versions)`\n- `tigervnc (all versions)`\n- `tigervnc (all versions)`\n- `xorg-x11-server`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n### Workarounds\n\nMitigation for this issue is either not available or the currently available options don't meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0.4,"exploitation":0,"ransomware":0},"changes":[]}