The remote Redhat Enterprise Linux 9 host has packages installed that are affected by multiple vulnerabilities as referenced in the RHSA-2026:26590 advisory.

    Xwayland is an X server for running X clients under Wayland.

    Security Fix(es):

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias     resolution due to libXfont2 name length mismatch (CVE-2026-50256)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence()     (CVE-2026-50257)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due     to unchecked shift levels (CVE-2026-50258)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request     via mapWidths indexing (CVE-2026-50259)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter()     (CVE-2026-50260)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter()     (CVE-2026-50261)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX     ChangeDrawableAttributes (CVE-2026-50262)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in     CreateSaverWindow() (CVE-2026-50263)

    * xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2     DRIGetBuffers/DRIGetBuffersWithFormat (CVE-2026-50264)

    Bug Fix(es) and Enhancement(s):

    * [xwayland] Backport other security fixes without a CVE assigned [rhel-9.8.z] (JIRA:RHEL-184292)

    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.

Tenable has extracted the preceding description block directly from the Red Hat Enterprise Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Detections

Analytics

RHEL 9 : xorg-x11-server-Xwayland (RHSA-2026:26590)

medium Nessus Plugin ID 321484

Version 1.1