Red Hat has issued an Important security update for xorg-x11-server-Xwayland on RHEL 9 to address three vulnerabilities (CVE-2026-33999, CVE-2026-34001, CVE-2026-34003), each with a CVSS 3.1 score of 7.8 (HIGH). These flaws include an integer underflow, a use-after-free, and an out-of-bounds memory access, which can lead to denial of service, server crashes, information exposure, and potential memory corruption. The update provides fixed packages, and affected systems should be patched following the Red Hat solution article.
Red Hat Product Errata RHSA-2026:11369 - Security Advisory Issued: 2026-04-28 Updated: 2026-04-28 RHSA-2026:11369 - Security Advisory Overview Updated Packages Synopsis Important: xorg-x11-server-Xwayland 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-Xwayland is now available for Red Hat Enterprise Linux 9. 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 Xwayland is an X server for running X clients under Wayland. Security Fix(es): xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling (CVE-2026-33999) xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption (CVE-2026-34001) xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access (CVE-2026-34003) 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 9 x86_64 Red Hat Enterprise Linux for IBM z Systems 9 s390x Red Hat Enterprise Linux for Power, little endian 9 ppc64le Red Hat Enterprise Linux for ARM 64 9 aarch64 Red Hat CodeReady Linux Builder for x86_64 9 x86_64 Red Hat CodeReady Linux Builder for Power, little endian 9 ppc64le Red Hat CodeReady Linux Builder for ARM 64 9 aarch64 Red Hat CodeReady Linux Builder for IBM z Systems 9 s390x Fixes BZ - 2451106 - CVE-2026-33999 xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling BZ - 2451109 - CVE-2026-34001 xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption BZ - 2451113 - CVE-2026-34003 xorg: xwayland: X.Org X server: Information exposure and denial of service via out-of-bounds memory access CVEs CVE-2026-33999 CVE-2026-34001 CVE-2026-34003 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 9 SRPM xorg-x11-server-Xwayland-23.2.7-6.el9_7.src.rpm SHA-256: 59857148b47687c6a7aa1006e8096148c205374f07f8e78ae3cd1fc08aa2fd1f x86_64 xorg-x11-server-Xwayland-23.2.7-6.el9_7.x86_64.rpm SHA-256: 16fc2b86a630f02af9bfde2ae5f40bcea2d9184a32b341e0439490394affa4b3 xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.x86_64.rpm SHA-256: fcff0108eb12bd3f9fcf41e0d84eab8a0667d68992abfa105fe29fa1ac85a684 xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.x86_64.rpm SHA-256: e26fda03ec9f5856d3bffe5ea490b50d20c016780ea0bede560bdab113e1c379 Red Hat Enterprise Linux for IBM z Systems 9 SRPM xorg-x11-server-Xwayland-23.2.7-6.el9_7.src.rpm SHA-256: 59857148b47687c6a7aa1006e8096148c205374f07f8e78ae3cd1fc08aa2fd1f s390x xorg-x11-server-Xwayland-23.2.7-6.el9_7.s390x.rpm SHA-256: 5330d2d8d88e0212372663471395a1241f931139257c2ed0935a7d17f16d268b xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.s390x.rpm SHA-256: d2fe0917374ffc1923e718ffd438c26faf5e7f7f3647641ba435c5146ac0faee xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.s390x.rpm SHA-256: 65436967d2a5980c1865b3da231792b69b2a70fe28544d972eab305fcc6e5195 Red Hat Enterprise Linux for Power, little endian 9 SRPM xorg-x11-server-Xwayland-23.2.7-6.el9_7.src.rpm SHA-256: 59857148b47687c6a7aa1006e8096148c205374f07f8e78ae3cd1fc08aa2fd1f ppc64le xorg-x11-server-Xwayland-23.2.7-6.el9_7.ppc64le.rpm SHA-256: ecb4fd3c4b8abef53816008d7b43b77d8274fb187a87bd78be6740595006724d xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.ppc64le.rpm SHA-256: e11060a5e691d9eaad53ab5b978aa8b84648e16a94a571d69234f13b07dc618b xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.ppc64le.rpm SHA-256: f9cd81aa22afe79696c911eb2daffb03948b1c06e250daf35810ec9f3525990b Red Hat Enterprise Linux for ARM 64 9 SRPM xorg-x11-server-Xwayland-23.2.7-6.el9_7.src.rpm SHA-256: 59857148b47687c6a7aa1006e8096148c205374f07f8e78ae3cd1fc08aa2fd1f aarch64 xorg-x11-server-Xwayland-23.2.7-6.el9_7.aarch64.rpm SHA-256: da5df8dce3b128fa50bf0532ae866c34519c2c798e66a62e777ae62783acf54a xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.aarch64.rpm SHA-256: 3c259c72c43a64220065277e98bf265ecd29dd55607c50f0630eeafcb396c810 xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.aarch64.rpm SHA-256: 7c9eee4fc8e794f79af2fe23a697613910899acf0a28b91f3b96f700e2148e46 Red Hat CodeReady Linux Builder for x86_64 9 SRPM x86_64 xorg-x11-server-Xwayland-23.2.7-6.el9_7.i686.rpm SHA-256: 62985380251e593d22c820f4cf90d7be3abb0bbe08f78291fdaed6e4788a3723 xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.i686.rpm SHA-256: 9267bd7fb4ff4e701eaa2b4aa0bc52bf29cc05c275777cc5118f7e05ebb63ce4 xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.x86_64.rpm SHA-256: fcff0108eb12bd3f9fcf41e0d84eab8a0667d68992abfa105fe29fa1ac85a684 xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.i686.rpm SHA-256: cfce556ce0af4a8afacafcd8eb22e3b4b5f28b970e32777e4cda44f20f77d14e xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.x86_64.rpm SHA-256: e26fda03ec9f5856d3bffe5ea490b50d20c016780ea0bede560bdab113e1c379 xorg-x11-server-Xwayland-devel-23.2.7-6.el9_7.i686.rpm SHA-256: b537e571941d3620f38682dac478c083abf5eb4aa94714b9be4c33b4d3281194 xorg-x11-server-Xwayland-devel-23.2.7-6.el9_7.x86_64.rpm SHA-256: 69f6064b682354672b06e9f55915d38c0d01dba916823b73f8ca2fcc6acfca56 Red Hat CodeReady Linux Builder for Power, little endian 9 SRPM ppc64le xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.ppc64le.rpm SHA-256: e11060a5e691d9eaad53ab5b978aa8b84648e16a94a571d69234f13b07dc618b xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.ppc64le.rpm SHA-256: f9cd81aa22afe79696c911eb2daffb03948b1c06e250daf35810ec9f3525990b xorg-x11-server-Xwayland-devel-23.2.7-6.el9_7.ppc64le.rpm SHA-256: 44544cbb868cfb794924412463543402d28b6f227bc1509d14b441920bb24874 Red Hat CodeReady Linux Builder for ARM 64 9 SRPM aarch64 xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.aarch64.rpm SHA-256: 3c259c72c43a64220065277e98bf265ecd29dd55607c50f0630eeafcb396c810 xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.aarch64.rpm SHA-256: 7c9eee4fc8e794f79af2fe23a697613910899acf0a28b91f3b96f700e2148e46 xorg-x11-server-Xwayland-devel-23.2.7-6.el9_7.aarch64.rpm SHA-256: a4985fcb71ceb7d15cdfbbe60a11fb750e1c8ac721ca114f6be621651fab90fb Red Hat CodeReady Linux Builder for IBM z Systems 9 SRPM s390x xorg-x11-server-Xwayland-debuginfo-23.2.7-6.el9_7.s390x.rpm SHA-256: d2fe0917374ffc1923e718ffd438c26faf5e7f7f3647641ba435c5146ac0faee xorg-x11-server-Xwayland-debugsource-23.2.7-6.el9_7.s390x.rpm SHA-256: 65436967d2a5980c1865b3da231792b69b2a70fe28544d972eab305fcc6e5195 xorg-x11-server-Xwayland-devel-23.2.7-6.el9_7.s390x.rpm SHA-256: 559da63bbf5652838df10c90df128ad7baffe4a656509ec8a0f35bd1248558d3 The Red Hat security contact is secalert@redhat.com . 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