Red Hat Product Errata RHSA-2026:36083 - Security Advisory Issued: 2026-07-07 Updated: 2026-07-07 RHSA-2026:36083 - 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 7 Extended Lifecycle 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 Server - Extended Life Cycle Support 7 x86_64 Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 s390x Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 ppc64 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 ppc64le 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 Server - Extended Life Cycle Support 7 SRPM xorg-x11-server-1.20.4-35.el7_9.src.rpm SHA-256: c3d7826b8d910cebcd008e996a50a6829c72283dca53dd72e76f5ca5bb443f73 x86_64 xorg-x11-server-Xdmx-1.20.4-35.el7_9.x86_64.rpm SHA-256: 1d4cfc59b26edb484e636ff880775a9e339ebd0ac31a9c887363a801e7122182 xorg-x11-server-Xephyr-1.20.4-35.el7_9.x86_64.rpm SHA-256: 9bfd727af721216b11febe511fc511f5e00dc014d5ebc96e136bd55211b34844 xorg-x11-server-Xnest-1.20.4-35.el7_9.x86_64.rpm SHA-256: 29fbb8d31b30b81c3d06d655e4d0302d84b412b59c27c0cb4f92b1043551205a xorg-x11-server-Xorg-1.20.4-35.el7_9.x86_64.rpm SHA-256: ea54994b164893ff4e04227a3490f210dd71a5877fe3d7a7173b4c225964fe05 xorg-x11-server-Xvfb-1.20.4-35.el7_9.x86_64.rpm SHA-256: 7b87f75f0dcb5c84887bcaad9561394d732f8e7384f8f83b1574274bfe1e7396 xorg-x11-server-Xwayland-1.20.4-35.el7_9.x86_64.rpm SHA-256: 140e898f9bc48c19da4ccdc8a235cfcb966495809b19b9a4ffa939badd8254fd xorg-x11-server-common-1.20.4-35.el7_9.x86_64.rpm SHA-256: a67bfce982dd19ac559510404fbc28f9de7c32ad71a0c20cedb4b9ddc8d19319 xorg-x11-server-debuginfo-1.20.4-35.el7_9.i686.rpm SHA-256: 776c0899118b30ed97aac34c3c750e1a6ba8359456e1073ce510034fe036c7cd xorg-x11-server-debuginfo-1.20.4-35.el7_9.x86_64.rpm SHA-256: f531ac996b98e93ad3cb465808a32bb94e11c687d752947e153286c4e1a853d3 xorg-x11-server-debuginfo-1.20.4-35.el7_9.x86_64.rpm SHA-256: f531ac996b98e93ad3cb465808a32bb94e11c687d752947e153286c4e1a853d3 xorg-x11-server-devel-1.20.4-35.el7_9.i686.rpm SHA-256: b3af00c814b67f9a71038fd5e3684e063eade14d4a80e7405d231b328d0fcf5a xorg-x11-server-devel-1.20.4-35.el7_9.x86_64.rpm SHA-256: 2c51792cd02b89ce43ef73f738465c739358ee50cb975ac41f882ea03e6c19b8 xorg-x11-server-source-1.20.4-35.el7_9.noarch.rpm SHA-256: ace73585e62c8939bab76b98759f7a507a85f7c50a5bb2ff2910e84a489b109b Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 SRPM xorg-x11-server-1.20.4-35.el7_9.src.rpm SHA-256: c3d7826b8d910cebcd008e996a50a6829c72283dca53dd72e76f5ca5bb443f73 s390x xorg-x11-server-Xdmx-1.20.4-35.el7_9.s390x.rpm SHA-256: ba9aa9f7912e32e92d243362ade7ffb1e031006c301bb14d7feb2c3afaa3cd51 xorg-x11-server-Xephyr-1.20.4-35.el7_9.s390x.rpm SHA-256: 0556a6bec3a9a82e1a2844f1c551e93d0840816b0fd5fc75b102727cf795979b xorg-x11-server-Xnest-1.20.4-35.el7_9.s390x.rpm SHA-256: c8736309767a95fd287eaf62e976f36bdba84790dd9eacf16e34a12bd27df27a xorg-x11-server-Xvfb-1.20.4-35.el7_9.s390x.rpm SHA-256: ecddc506bdeb5aaf36885a7999277adb0328602f3f30cbffd36211f9d34ef886 xorg-x11-server-Xwayland-1.20.4-35.el7_9.s390x.rpm SHA-256: b81dc8f1217960f54257feb863b90ed0a791b5815a94ca5c585fc0744c5996b1 xorg-x11-server-common-1.20.4-35.el7_9.s390x.rpm SHA-256: 9175b3740b9ea610a893db34cbfeddbaeb8ba2c29f898b793eabf6731d07c486 xorg-x11-server-debuginfo-1.20.4-35.el7_9.s390x.rpm SHA-256: ac50321a4d969ae723ccf3c517320ee85447afae2a69cf13375ce38e44d56200 xorg-x11-server-debuginfo-1.20.4-35.el7_9.s390x.rpm SHA-256: ac50321a4d969ae723ccf3c517320ee85447afae2a69cf13375ce38e44d56200 xorg-x11-server-source-1.20.4-35.el7_9.noarch.rpm SHA-256: ace73585e62c8939bab76b98759f7a507a85f7c50a5bb2ff2910e84a489b109b Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 SRPM xorg-x11-server-1.20.4-35.el7_9.src.rpm SHA-256: c3d7826b8d910cebcd008e996a50a6829c72283dca53dd72e76f5ca5bb443f73 ppc64 xorg-x11-server-Xdmx-1.20.4-35.el7_9.ppc64.rpm SHA-256: 240d96a15a02e12e021205a5a2d6f198c26b8272c211ae86895a3a2020f89448 xorg-x11-server-Xephyr-1.20.4-35.el7_9.ppc64.rpm SHA-256: a02c3437fb62113717f260ad9abcf42c032c17e9c2202045ac91f91dd6ddd10a xorg-x11-server-Xnest-1.20.4-35.el7_9.ppc64.rpm SHA-256: d394bfc8a0fe589b63828459b5a19bde52b7fe7286a804164b78dbd0531a530b xorg-x11-server-Xorg-1.20.4-35.el7_9.ppc64.rpm SHA-256: c9f7b26fd23c33ddab06cafb60f34291d25da053736c60ff97da86a4c1fad57e xorg-x11-server-Xvfb-1.20.4-35.el7_9.ppc64.rpm SHA-256: 9672e6a1881c20f07b2b71ca0acd4152ca6f9146009468f66094cfbd13896743 xorg-x11-server-Xwayland-1.20.4-35.el7_9.ppc64.rpm SHA-256: d6b30e2a40468ca2913e2669793a5f727a54d9ec6ef2bc1aed945116dfb21a28 xorg-x11-server-common-1.20.4-35.el7_9.ppc64.rpm SHA-256: 12e5a79b56253b14ab128b02f189c78470feba8373aabf68eb468ea789ba75e9 xorg-x11-server-debuginfo-1.20.4-35.el7_9.ppc.rpm SHA-256: f75944b9e6b2d75cb715dc71423a68a5db10edd3267ec66a2855cf5635aeec67 xorg-x11-server-debuginfo-1.20.4-35.el7_9.ppc64.rpm SHA-256: cde362158dde35d933120340a5c0f44eec25dcd6c4bfaa2e9490aa8a3abef60a xorg-x11-server-debuginfo-1.20.4-35.el7_9.ppc64.rpm SHA-256: cde362158dde35d933120340a5c0f44eec25dcd6c4bfaa2e9490aa8a3abef60a xorg-x11-server-devel-1.20.4-35.el7_9.ppc.rpm SHA-256: 01369aac0dd629534953006009e7bca2f1b98b185d13834d4fcd21fff2ce83c2 xorg-x11-server-devel-1.20.4-35.el7_9.ppc64.rpm SHA-256: ea6e053b35b72af0333bd9bca019dfdb1fe77096db869c999dd05a31688aabc6 xorg-x11-server-source-1.20.4-35.el7_9.noarch.rpm SHA-256: ace73585e62c8939bab76b98759f7a507a85f7c50a5bb2ff2910e84a489b109b Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 SRPM xorg-x11-server-1.20.4-35.el7_9.src.rpm SHA-256: c3d7826b8d910cebcd008e996a50a6829c72283dca53dd72e76f5ca5bb443f73 ppc64le xorg-x11-server-Xdmx-1.20.4-35.el7_9.ppc64le.rpm SHA-256: 0f438fb82c94a73624b996015656efd321a0ebee8cbc051c99584844dafc2381 xorg-x11-server-Xephyr-1.20.4-35.el7_9.ppc64le.rpm SHA-256: ae47778fdc7fdd12d3013ce179f65a8934f450f13afd6f09fef6d4d872dafeaf xorg-x11-server-Xnest-1.20.4-35.el7_9.ppc64le.rpm SHA-25