- Issued:
- 2026-07-07
- Updated:
- 2026-07-07
RHSA-2026:36083 - Security Advisory
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.
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:
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
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-256: b87782bd04f586be1c9960ea34b5e490270ccda5d5a21d3222facbdd34f2893e |
| xorg-x11-server-Xorg-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: ee0f9b2c7f956933e7a7bb85ff43520dcdce51c645cbd7f96102925a90707d66 |
| xorg-x11-server-Xvfb-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: a35723b517901e504a86110cd180a58b5860e51499de863d80399ef5df83d3c5 |
| xorg-x11-server-Xwayland-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: cc1b6cc96a7cac71333cab0077377a9227eead8290824e44c47898ef904a40e5 |
| xorg-x11-server-common-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: aba88e2d1af418d82269d9c4fbe8ed6bc8d539a149b148fc5f136344f8db4fb4 |
| xorg-x11-server-debuginfo-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: fabc894e310bd95f7dff6a1f9dd8dc5e958a50b4fdadbf08767a73b84c2dfbc3 |
| xorg-x11-server-debuginfo-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: fabc894e310bd95f7dff6a1f9dd8dc5e958a50b4fdadbf08767a73b84c2dfbc3 |
| xorg-x11-server-devel-1.20.4-35.el7_9.ppc64le.rpm | SHA-256: 1f660fc033ada3a317fb3b867ab6ea53fce8462833e120ca39bb9c954d94c5a3 |
| xorg-x11-server-source-1.20.4-35.el7_9.noarch.rpm | SHA-256: ace73585e62c8939bab76b98759f7a507a85f7c50a5bb2ff2910e84a489b109b |
The Red Hat security contact is secalert@redhat.com. More contact details at https://access.redhat.com/security/team/contact/.
