Red Hat Product Errata RHSA-2026:36087 - Security Advisory Issued: 2026-07-07 Updated: 2026-07-07 RHSA-2026:36087 - 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 9.4 Update Services for SAP Solutions. 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 - AUS 9.4 x86_64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.4 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.4 x86_64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.4 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.4 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.4 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.4 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.4 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.4 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 Server - AUS 9.4 SRPM xorg-x11-server-1.20.11-29.el9_4.src.rpm SHA-256: 7686885dc3de2788543f50235379faa72737cc900cc5198ff9e975300da0bfbd x86_64 xorg-x11-server-Xdmx-1.20.11-29.el9_4.x86_64.rpm SHA-256: a3be17723ef6b9792c68251f679b9e3adaa495b218afdc32e2fc3f74d92fca11 xorg-x11-server-Xdmx-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 05a22d9629e37c5e8d2e9b0aa6d0ddf3b820936f4c50cb7666538fa10e8fd4a6 xorg-x11-server-Xephyr-1.20.11-29.el9_4.x86_64.rpm SHA-256: 645ca2f61687668f9dafc6c6c25114439715a9320a51558b0a41fb587523ae4c xorg-x11-server-Xephyr-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 2434253faae12d078697ffec848413cfc5356fc6555a7fe91075e4397cc0d4a1 xorg-x11-server-Xnest-1.20.11-29.el9_4.x86_64.rpm SHA-256: c9caac780b449218f421433fd0c41a4b2f408f99af0b95f18f9e46c1b0e223fb xorg-x11-server-Xnest-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 7455a0b739d2f05dffa2119dd00bca64abcb40f6156dfc4459b021f9de1609e1 xorg-x11-server-Xorg-1.20.11-29.el9_4.x86_64.rpm SHA-256: 24807aeb4bc23925087e94586477ed060326cbcd09fbddcc60fde72b0d60cfdc xorg-x11-server-Xorg-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 78f0392ad47099d7bb62040af70e77a9a824c4a44b30f22e24a3b418de1e92d5 xorg-x11-server-Xvfb-1.20.11-29.el9_4.x86_64.rpm SHA-256: 40c2aa6a28d770073e0519f142a8f9f061227daa5554f5b0e1c510e6fd31bf67 xorg-x11-server-Xvfb-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 7ab34952b776f898bb49ccb98ceb8b0ec55305b887a90a03ba912ffbb605cc59 xorg-x11-server-common-1.20.11-29.el9_4.x86_64.rpm SHA-256: c3750b8251fe5dfc4e98012c12fbfebe449796c4421e5d594396600507453b48 xorg-x11-server-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 4a1f6aa5fcad2a9e562238c3951526dd89a15181844cc3b0ef3b07152e9dc92a xorg-x11-server-debugsource-1.20.11-29.el9_4.x86_64.rpm SHA-256: 85fd7dfba3d1f697f9115f1bff5477993d72c4d8945ed4e952dafb84cd900fb2 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.4 SRPM xorg-x11-server-1.20.11-29.el9_4.src.rpm SHA-256: 7686885dc3de2788543f50235379faa72737cc900cc5198ff9e975300da0bfbd ppc64le xorg-x11-server-Xdmx-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 00382197997edb255a3c37d1a9d1b75ca61f3817062eedbd977c8ea2faee7ed3 xorg-x11-server-Xdmx-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 088556d05dd556ce9be8233d55262d1b1c425201bdc51bda47e428a8c09c0d70 xorg-x11-server-Xephyr-1.20.11-29.el9_4.ppc64le.rpm SHA-256: a3c3eecab1e43e252152ff2ee839101d9683ba3f14851f9c8f465983660b542d xorg-x11-server-Xephyr-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: cbce3400437c4a9bb3ddf9132a546be8113a94f1b45fa3e81b6ddc94fdaefa35 xorg-x11-server-Xnest-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 3f6ad10ab6574b1b100f61a465ae1b1555391db8be14220003dfbe9e012217c0 xorg-x11-server-Xnest-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 7ee920c659f6ac6aba2ed3947510e4d1f8440837884ae3aaadaa3b7e83e4602d xorg-x11-server-Xorg-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 7119d6d379aa3187594a0e1516dce34c797621a68f70f70605b0f68b0f150bd8 xorg-x11-server-Xorg-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 9e8045e1add54765e7d05562ded3ad9343c9edfde66d96a69f03cde67a5619db xorg-x11-server-Xvfb-1.20.11-29.el9_4.ppc64le.rpm SHA-256: aec3f00928c6286884bf311ba824c77550fcbff9e5e95b8c010bc57ae600d4bb xorg-x11-server-Xvfb-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 11869e7084cc1a5136f4b6dd2b0ee6b66a043af3163baa15ab37a9af978d06ae xorg-x11-server-common-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 2dd0aa94d0431715f36e09d7c5a37c39a5d70b7a45a0fe14ee358184a1066587 xorg-x11-server-debuginfo-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 96b0e8bd914f836b3c26907306706609ae0032a708b8c3ad68d2e7c29e83a2cb xorg-x11-server-debugsource-1.20.11-29.el9_4.ppc64le.rpm SHA-256: 8234ed35d1cbf879afa9f1879da4cbbee60b264661f3661f7d997de1c65f8e3c Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.4 SRPM xorg-x11-server-1.20.11-29.el9_4.src.rpm SHA-256: 7686885dc3de2788543f50235379faa72737cc900cc5198ff9e975300da0bfbd x86_64 xorg-x11-server-Xdmx-1.20.11-29.el9_4.x86_64.rpm SHA-256: a3be17723ef6b9792c68251f679b9e3adaa495b218afdc32e2fc3f74d92fca11 xorg-x11-server-Xdmx-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 05a22d9629e37c5e8d2e9b0aa6d0ddf3b820936f4c50cb7666538fa10e8fd4a6 xorg-x11-server-Xephyr-1.20.11-29.el9_4.x86_64.rpm SHA-256: 645ca2f61687668f9dafc6c6c25114439715a9320a51558b0a41fb587523ae4c xorg-x11-server-Xephyr-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 2434253faae12d078697ffec848413cfc5356fc6555a7fe91075e4397cc0d4a1 xorg-x11-server-Xnest-1.20.11-29.el9_4.x86_64.rpm SHA-256: c9caac780b449218f421433fd0c41a4b2f408f99af0b95f18f9e46c1b0e223fb xorg-x11-server-Xnest-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 7455a0b739d2f05dffa2119dd00bca64abcb40f6156dfc4459b021f9de1609e1 xorg-x11-server-Xorg-1.20.11-29.el9_4.x86_64.rpm SHA-256: 24807aeb4bc23925087e94586477ed060326cbcd09fbddcc60fde72b0d60cfdc xorg-x11-server-Xorg-debuginfo-1.20.11-29.el9_4.x86_64.rpm SHA-256: 78f0392ad47099d7bb62040af70e77a9a824c4a44b30f22e24a3b418de1e92d5 xorg-x11-server-Xvfb-1.20.11-29.el9_4.x86_64.rpm SHA-256: 40c2aa6a28d770073e0519f142a8f9f061227daa5554f5b0e1c510e6fd31bf67 xorg-x11-server-Xvfb-debuginfo-1.20.11-29.el9_4.x86