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High ALSA-2026:84574 5 CVEs

Important: xorg-x11-server security update

Published Oct 19, 2026 · Updated Oct 29, 2026

Ecosystem: AlmaLinux

Summary

X.Org is an open-source implementation of the X Window System. It provides the basic low-level functionality that full-fledged graphical user interfaces are designed upon.

Security Fix(es):

* xorg-x11-server: xorg-x11-server: Arbitrary code execution via use-after-free in passive grab handling (CVE-2026-93516)
* xorg-x11-server: xorg-x11-server: arbitrary code execution via GLX RenderLarge heap-based buffer overflow (CVE-2026-93517)
* xorg-x11-server: xorg-x11-server: arbitrary code execution via integer truncation during keyboard mapping resize (CVE-2026-93518)
* xorg-x11-server: xorg-x11-server: Arbitrary code execution via buffer overflow in input_constrain_cursor() (CVE-2026-93519)
* xorg-x11-server: xorg-x11-server: arbitrary code execution via out-of-bounds write in XKB keycode handling (CVE-2026-93520)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Fixed packages 8

ReleasePackageFixed in
AlmaLinux · 9 xorg-x11-server-common 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-devel 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-source 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-Xdmx 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-Xephyr 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-Xnest 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-Xorg 1.20.11-34.el9_8.5
AlmaLinux · 9 xorg-x11-server-Xvfb 1.20.11-34.el9_8.5

Vulnerabilities 5

  • High 8.5
    CVE-2026-93517

    X.Org Server GLX RenderLarge Heap Buffer Overflow

    A heap buffer overflow in handling GLX RenderLarge request where dataBytes exceeds cmdlen in X.org X server before 21.1.25 and XWayland before 24.1.14 that could be be triggered by an authenticated X client could cause crashes or code execution in X server co…

    X.Org x.orgg xwayland xorg-x11-server Debian Ubuntu Azure Linux Alpine
  • High 7.8
    CVE-2026-93518

    X.Org Server XKB ResizeKeyType Numeric Truncation

    An integer truncation issue in XkbResizeKeyType() that could lead to a heap buffer overflow by authenticated X clients in X.org X server before 21.1.25 and XWayland before 24.1.14 could be exploited for crashes or potential code execution in the X server.

    X.Org xwayland xorg-x11-server xorg-server Debian Ubuntu Azure Linux Alpine
  • High 7.8
    CVE-2026-93519

    X.Org Server XFixes Pointer Barrier Event List Buffer Overflow

    A buffer overflow when handling pointer barriers in the XFIXES extension in X.Org X server before 21.1.25 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server context.

    X.Org x.orgg xorg-x11-server xwayland Debian Ubuntu Azure Linux Alpine
  • High 7.8
    CVE-2026-93520

    X.Org Server XKB ChangeKeycodeRange Heap Out-of-Bounds Write

    A heap buffer overflow caused by mismatching size calculations between XkbAllocNames and ChangeKeycodeRange in X.org X server before 2.1.25 and XWayland before 24.1.14 could be used by authenticated X clients to crash or potentially execute code in X server c…

    X.Org xwayland xorg-x11-server xorg-server Debian Ubuntu Azure Linux Alpine
  • Medium 5.5
    CVE-2026-93516

    .Org Server XInput Passive Grab Use-After-Free

    A use-after-free caused by lack of lifecycle management when adding / removing XInput master devices in X.org X Server before 21.1.25 and XWayland before 24.1.14 could be used by authenticated X Clients to crash the X server or potentially execute code in X s…

    X.Org xwayland xorg-x11-server xorg-server Debian Ubuntu Azure Linux Alpine

References

  • report
    https://access.redhat.com/security/cve/CVE-2026-93516
  • report
    https://access.redhat.com/security/cve/CVE-2026-93517
  • report
    https://access.redhat.com/security/cve/CVE-2026-93518
  • report
    https://access.redhat.com/security/cve/CVE-2026-93519
  • report
    https://access.redhat.com/security/cve/CVE-2026-93520
  • report
    https://bugzilla.redhat.com/2545161
  • report
    https://bugzilla.redhat.com/2545246
  • report
    https://bugzilla.redhat.com/2545860
  • report
    https://bugzilla.redhat.com/2545887
  • report
    https://bugzilla.redhat.com/2545908
  • advisory
    https://errata.almalinux.org/9/ALSA-2026-84574.html