Red Hat Product Errata RHSA-2026:36085 - Security Advisory Issued: 2026-07-07 Updated: 2026-07-07 RHSA-2026:36085 - Security Advisory Overview Updated Packages Synopsis Important: xorg-x11-server security update Type/Severity Security Advisory: Important Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for xorg-x11-server is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section. Description 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-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) 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. Solution For details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258 Affected Products Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.6 x86_64 Red Hat Enterprise Linux Server - AUS 9.6 x86_64 Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.6 s390x Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.6 ppc64le Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.6 aarch64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.6 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.6 x86_64 Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 9.6 x86_64 Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 9.6 ppc64le Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 9.6 s390x Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 9.6 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.6 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.6 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.6 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.6 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.6 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.6 s390x Fixes BZ - 2485380 - CVE-2026-50256 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch BZ - 2485382 - CVE-2026-50257 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in miSyncDestroyFence() BZ - 2485383 - CVE-2026-50258 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB key types due to unchecked shift levels BZ - 2485384 - CVE-2026-50259 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in XKB SetMap request via mapWidths indexing BZ - 2485385 - CVE-2026-50260 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in FreeCounter() BZ - 2485386 - CVE-2026-50261 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free in SyncChangeCounter() BZ - 2485387 - CVE-2026-50262 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds read/write in GLX ChangeDrawableAttributes BZ - 2485388 - CVE-2026-50263 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: use-after-free information disclosure in CreateSaverWindow() BZ - 2485389 - CVE-2026-50264 xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: out-of-bounds heap write in DRI2 DRIGetBuffers/DRIGetBuffersWithFormat CVEs CVE-2026-50256 CVE-2026-50257 CVE-2026-50258 CVE-2026-50259 CVE-2026-50260 CVE-2026-50261 CVE-2026-50262 CVE-2026-50263 CVE-2026-50264 References https://access.redhat.com/security/updates/classification/#important Note: More recent versions of these packages may be available. Click a package name for more details. Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.6 SRPM xorg-x11-server-1.20.11-34.el9_6.src.rpm SHA-256: 6f25fa125849603567893905febae6fe72db1d73047d85d9fcbaa8ad512a3261 x86_64 xorg-x11-server-Xdmx-1.20.11-34.el9_6.x86_64.rpm SHA-256: ce75cd8c4ae5eb570e373618b66e10f0e709bfea27d97f189d2700a655e604a6 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 2886e713794f97a6b7404a857c90eaaacd9ac8f32f0187e44b00d674a8186570 xorg-x11-server-Xephyr-1.20.11-34.el9_6.x86_64.rpm SHA-256: d69054ae2a6d087a624e33afc9dccbef91884ee0881f1ad56505fbf8f0f3eeae xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: ae306798957d155e0b3fab90ad4233c58b98454efbb501eba09934695fb841e5 xorg-x11-server-Xnest-1.20.11-34.el9_6.x86_64.rpm SHA-256: 0829e21c95fbb4549a799de7c33153ca7590cf03bd34f243a4e6324ab995fd7f xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 64a967627c7a2906c1723602922d8a573d14e770f85a1213f01c52577d6c3b9a xorg-x11-server-Xorg-1.20.11-34.el9_6.x86_64.rpm SHA-256: bbff8607b65e53382ae77c7949991c4e4cfffe9fa0307c2528a0292789205227 xorg-x11-server-Xorg-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: fa1fd763acb260963b6142b88a6d8a2ce3aa452106c437949a9ce790d9c02c78 xorg-x11-server-Xvfb-1.20.11-34.el9_6.x86_64.rpm SHA-256: f74c3d84b06be6aacd45d9e2cefdf6ef3a2c26f66bea0b31b5b98973621cba9e xorg-x11-server-Xvfb-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 5ebbed2be30b9993e5d78b608cb798657642865372d0140800bbf9eeee0bf5f7 xorg-x11-server-common-1.20.11-34.el9_6.x86_64.rpm SHA-256: acbb06848c856f19f988ada696a9f02139b30696d68768a02d748892251dde17 xorg-x11-server-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 4c8097b2fcc6430de6fa3223d7ea9e08e336c2c675e68decaeb3c5df98d39611 xorg-x11-server-debugsource-1.20.11-34.el9_6.x86_64.rpm SHA-256: 66fed1963360569abda85941a5801b68c0fdeeefadd0795f8d336ce6f285f04f Red Hat Enterprise Linux Server - AUS 9.6 SRPM xorg-x11-server-1.20.11-34.el9_6.src.rpm SHA-256: 6f25fa125849603567893905febae6fe72db1d73047d85d9fcbaa8ad512a3261 x86_64 xorg-x11-server-Xdmx-1.20.11-34.el9_6.x86_64.rpm SHA-256: ce75cd8c4ae5eb570e373618b66e10f0e709bfea27d97f189d2700a655e604a6 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 2886e713794f97a6b7404a857c90eaaacd9ac8f32f0187e44b00d674a8186570 xorg-x11-server-Xephyr-1.20.11-34.el9_6.x86_64.rpm SHA-256: d69054ae2a6d087a624e33afc9dccbef91884ee0881f1ad56505fbf8f0f3eeae xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: ae306798957d155e0b3fab90ad4233c58b98454efbb501eba09934695fb841e5 xorg-x11-server-Xnest-1.20.11-34.el9_6.x86_64.rpm SHA-256: 0829e21c95fbb4549a799de7c33153ca7590cf03bd34f243a4e6324ab995fd7f xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 64a967627c7a2906c1723602922d8a573d14e770f85a1213f01c52577d6c3b9a xorg-x11-server-Xorg-1.20.11-34.el9_6.x86_64.rpm SHA-256: bbff8607b65e53382ae77c7949991c4e4cfffe9fa0307c2528a0292789205227 xorg-x11-server-Xorg-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: fa1fd763acb260963b6142b88a6d8a2ce3aa452106c437949a9ce790d9c02c78 xorg-x11-server-Xvfb-1.20.11-34.el9_6.x86_64.rpm SHA-256: f74c3d84b06be6aacd45d9e2cefdf6ef3a2c26f66bea0b31b5b98973621cba9e xorg-x11-server-Xvfb-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 5ebbed2be30b9993e5d78b608cb798657642865372d0140800bbf9eeee0bf5f7 xorg-x11-server-common-1.20.11-34.el9_6.x86_64.rpm SHA-256: acbb06848c856f19f988ada696a9f02139b30696d68768a02d748892251dde17 xorg-x11-server-debuginfo-1.20.11-34.el9_6.x86_64.rpm SHA-256: 4c8097b2fcc6430de6fa3223d7ea9e08e336c2c675e68decaeb3c5df98d39611 xorg-x11-server-debugsource-1.20.11-34.el9_6.x86_64.rpm SHA-256: 66fed1963360569abda85941a5801b68c0fdeeefadd0795f8d336ce6f285f04f Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.6 SRPM xorg-x11-server-1.20.11-34.el9_6.src.rpm SHA-256: 6f25fa125849603567893905febae6fe72db1d73047d85d9fcbaa8ad512a3261 s390x xorg-x11-server-Xdmx-1.20.11-34.el9_6.s390x.rpm SHA-256: 4fceeb9e749a29f39ef1831a9384fff5634ddc58fbeffdcd027faefece0c2340 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_6.s390x.rpm SHA-256: 5a543e8bf94b24061c2acb58ea2b95f8e35f5a8fc307c4ac81efb8b9000edac8 xorg-x11-server-Xephyr-1.20.11-34.el9_6.s390x.rpm SHA-256: 9503611a553f120cabef13bdeb9ea72efe44f268a32c2be28c591f46069f9dbc xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_6.s390x.rpm SHA-256: acf87d690ef6aa2783b95271beeaeb70bf1344d64261ece80388748732007b4e xorg-x11-server-Xnest-1.20.11-34.el9_6.s390x.rpm SHA-256: 9fca7211ac7c8e1f834fe723d