This security update addresses five vulnerabilities in the X.Org X server's XWayland component, including high-severity issues (CVSS 7.8) such as an integer underflow and a use-after-free that can lead to denial of service, memory corruption, and information disclosure. The affected versions are Red Hat Enterprise Linux 7.0 under Extended Lifecycle Support. The advisory provides a patch to remediate these flaws; administrators should apply the update referenced in the Red Hat solution link.
Red Hat Product Errata RHSA-2026:20590 - Security Advisory Issued: 2026-05-26 Updated: 2026-05-26 RHSA-2026:20590 - 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: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling (CVE-2026-33999) xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in XKB geometry processing. (CVE-2026-34000) 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 disclosure or Denial of Service via out-of-bounds read in XKB modifier map handling (CVE-2026-34002) 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 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 - 2451106 - CVE-2026-33999 xorg: xwayland: X.Org X server: Denial of Service via integer underflow in XKB compatibility map handling BZ - 2451107 - CVE-2026-34000 xwayland: xorg: X.Org X server: Information disclosure and denial of service via out-of-bounds read in XKB geometry processing. BZ - 2451109 - CVE-2026-34001 xorg: xwayland: X.Org X server: Use-after-free vulnerability leads to server crash and potential memory corruption BZ - 2451112 - CVE-2026-34002 xorg: xwayland: X.Org X server: Information disclosure or Denial of Service via out-of-bounds read in XKB modifier map handling 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-2026-34000 CVE-2026-34001 CVE-2026-34002 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 Server - Extended Life Cycle Support 7 SRPM xorg-x11-server-1.20.4-34.el7_9.src.rpm SHA-256: c4040658c19abcf481b2c2963fecc9ab0db68ba3c405e802e4f531bb150a8836 x86_64 xorg-x11-server-Xdmx-1.20.4-34.el7_9.x86_64.rpm SHA-256: c22eaf92e8a1d51615620a531b83272a72a7bd0fec91cab9d891be1835120bf2 xorg-x11-server-Xephyr-1.20.4-34.el7_9.x86_64.rpm SHA-256: 98f07b3ecc1e07d5af2e9829eeade13e3cc1d2de3dbacd43d87ae61723ad49d2 xorg-x11-server-Xnest-1.20.4-34.el7_9.x86_64.rpm SHA-256: b5bf377b70a714cfdf31f62d8a92d32c020d32ff1029adbd2a7ac19c63b56ff4 xorg-x11-server-Xorg-1.20.4-34.el7_9.x86_64.rpm SHA-256: 2994ff6186f267b5982f42623b4711945a862fb92b2e90985e583b50bacb52f6 xorg-x11-server-Xvfb-1.20.4-34.el7_9.x86_64.rpm SHA-256: 1488aaa4e33305b652925a20b7ed41f7f6a7634e7bc1e6f587202c60f0b26940 xorg-x11-server-Xwayland-1.20.4-34.el7_9.x86_64.rpm SHA-256: 9da8711d5948fe4ff57697766b7c43da681385bf62c1e71fe035b6b39d91da45 xorg-x11-server-common-1.20.4-34.el7_9.x86_64.rpm SHA-256: d0af7236b7ce84fe744307ed514664c611376241982406d3cffc745bbe781cd2 xorg-x11-server-debuginfo-1.20.4-34.el7_9.i686.rpm SHA-256: ba1c2c301b97cec3baa7a57e867167505b0ee3dbda64e8b84f12f4e306229ed2 xorg-x11-server-debuginfo-1.20.4-34.el7_9.x86_64.rpm SHA-256: 5258b27f7d1f8dcd820aa0bdacc9aca5ef46920100bd20dbf2605cc57ed1ead2 xorg-x11-server-debuginfo-1.20.4-34.el7_9.x86_64.rpm SHA-256: 5258b27f7d1f8dcd820aa0bdacc9aca5ef46920100bd20dbf2605cc57ed1ead2 xorg-x11-server-devel-1.20.4-34.el7_9.i686.rpm SHA-256: 9de5570c0fef57aad973a37c549111d26dd90e6a2c5f0c710e06211c373ab62c xorg-x11-server-devel-1.20.4-34.el7_9.x86_64.rpm SHA-256: 26a6dfb19dd976145bc6bf039be78ffa6261322c4c1a71b3db8a46beacb16321 xorg-x11-server-source-1.20.4-34.el7_9.noarch.rpm SHA-256: 27e98b99ab2459357db2fe9156555923bdc1177d0d46cb8cc885ea0d09bebdd8 Red Hat Enterprise Linux Server - Extended Life Cycle Support (for IBM z Systems) 7 SRPM xorg-x11-server-1.20.4-34.el7_9.src.rpm SHA-256: c4040658c19abcf481b2c2963fecc9ab0db68ba3c405e802e4f531bb150a8836 s390x xorg-x11-server-Xdmx-1.20.4-34.el7_9.s390x.rpm SHA-256: 567f113e883a45ef43610cc8eb7d5b613b4f987f608b07fe3befc4428a593823 xorg-x11-server-Xephyr-1.20.4-34.el7_9.s390x.rpm SHA-256: 0df6deacf96220e467ffe980530e16bb7120c6957e93ecb8c673a4f7e0203e71 xorg-x11-server-Xnest-1.20.4-34.el7_9.s390x.rpm SHA-256: 109cf70d4563390c87756937a6e3012717cb7c81c2794a8a7e0bd2325a3e81fd xorg-x11-server-Xvfb-1.20.4-34.el7_9.s390x.rpm SHA-256: d42671d728945e09cff48e681299b9e25a01155259c751ffad0d562fdf7cc4ad xorg-x11-server-Xwayland-1.20.4-34.el7_9.s390x.rpm SHA-256: fc6b40f5b6b1931056f380ce67670bd9d161c1e1ba2312fb2aa13ab12cc34171 xorg-x11-server-common-1.20.4-34.el7_9.s390x.rpm SHA-256: ae45f126fce35c8c330170f0d0257450d0a9d8b8f7916dd35332fa1b641c03d8 xorg-x11-server-debuginfo-1.20.4-34.el7_9.s390x.rpm SHA-256: cb14e0b50a0b52d450243f2522b48dbd50e732d70e1463c55d5c30c297b6cecf xorg-x11-server-debuginfo-1.20.4-34.el7_9.s390x.rpm SHA-256: cb14e0b50a0b52d450243f2522b48dbd50e732d70e1463c55d5c30c297b6cecf xorg-x11-server-source-1.20.4-34.el7_9.noarch.rpm SHA-256: 27e98b99ab2459357db2fe9156555923bdc1177d0d46cb8cc885ea0d09bebdd8 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, big endian 7 SRPM xorg-x11-server-1.20.4-34.el7_9.src.rpm SHA-256: c4040658c19abcf481b2c2963fecc9ab0db68ba3c405e802e4f531bb150a8836 ppc64 xorg-x11-server-Xdmx-1.20.4-34.el7_9.ppc64.rpm SHA-256: 6f6f6524a1fb48b170033dc768270ee6085f0e3c135699198e3526769f1955ce xorg-x11-server-Xephyr-1.20.4-34.el7_9.ppc64.rpm SHA-256: d9d408f1ba0d026ca6519e7dba759159243dc6229da462674d8ab90282f97b0d xorg-x11-server-Xnest-1.20.4-34.el7_9.ppc64.rpm SHA-256: e465185265078d7a72463a828ec8cc4080c266ed243efda14d23d48353401fe7 xorg-x11-server-Xorg-1.20.4-34.el7_9.ppc64.rpm SHA-256: d6ca7d95afccc09fcc2076c5c097d1e7ae97f24c4d8e1f0a36328be57e9a7d7e xorg-x11-server-Xvfb-1.20.4-34.el7_9.ppc64.rpm SHA-256: db08171c51ef809c4482beaba2f2d81b0e0f13aa6c84a224997b9a2bacc53858 xorg-x11-server-Xwayland-1.20.4-34.el7_9.ppc64.rpm SHA-256: c04181b428602e5aad3ccd3c42182bcb24d0d9455499c11c92c16bbe2dbfbc7d xorg-x11-server-common-1.20.4-34.el7_9.ppc64.rpm SHA-256: 86deca520e8302b0eab1dc64c2f1d2b8d9a2c5a65ad6aa4fbf397ebea735d022 xorg-x11-server-debuginfo-1.20.4-34.el7_9.ppc.rpm SHA-256: fdd076df55e56e253a7046527aa1d895ef78eb983bba658e154b7b6be48a6150 xorg-x11-server-debuginfo-1.20.4-34.el7_9.ppc64.rpm SHA-256: f40360c9e1212da56c1207affed09afa04690430dfc58954b24e31c124f28f24 xorg-x11-server-debuginfo-1.20.4-34.el7_9.ppc64.rpm SHA-256: f40360c9e1212da56c1207affed09afa04690430dfc58954b24e31c124f28f24 xorg-x11-server-devel-1.20.4-34.el7_9.ppc.rpm SHA-256: 2051680dda10520863f6d1ff5f4a64cee8f2fbc6ea885352497a608beffb115b xorg-x11-server-devel-1.20.4-34.el7_9.ppc64.rpm SHA-256: ff5ccefda8f59b007af61145e31d10135c6eb60c0033598e2ae692224d1137b9 xorg-x11-server-source-1.20.4-34.el7_9.noarch.rpm SHA-256: 27e98b99ab2459357db2fe9156555923bdc1177d0d46cb8cc885ea0d09bebdd8 Red Hat Enterprise Linux Server - Extended Life Cycle Support for IBM Power, little endian 7 SRPM xorg-x11-server-1.20.4-34.el7_9.src.rpm SHA-256: c4040658c19abcf481b2c2963fecc9ab0db68ba3c405e802e4f531bb150a8836 ppc64le xorg-x11-server-Xdmx-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 17ab4b3ff4dc2aea0c1850b0e015c4e509d2fb6627091518213ed38b60740ff6 xorg-x11-server-Xephyr-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 564f82fac2ea30dce4760d2bf678bd902742eac4cecb94e4fa0bf042bed20fcd xorg-x11-server-Xnest-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 9632a6053c55f80cc9746f863bbdd6f4cb4b10844dcaf6b75ee0e35749f279a6 xorg-x11-server-Xorg-1.20.4-34.el7_9.ppc64le.rpm SHA-256: a8ab9f2ddf91efae131ac6fdb8828e88c8c097b68e297f1f786a2ce1442391be xorg-x11-server-Xvfb-1.20.4-34.el7_9.ppc64le.rpm SHA-256: bcfda30c2247c1f4b6101b4c521d0e2da6af3c3e74dad39fed939279af694953 xorg-x11-server-Xwayland-1.20.4-34.el7_9.ppc64le.rpm SHA-256: fdd0975bc866c1afa746b5f86a5adcd07cdb8839580df632ff3136df1d06316b xorg-x11-server-common-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 20756f718bb51dbe31795e42155ce094d0fcc885862f619919dd61a9f98136e9 xorg-x11-server-debuginfo-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 518b98e4c23890c8e7cf985be2c0639be28cc993ab30d8215373cab23d769991 xorg-x11-server-debuginfo-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 518b98e4c23890c8e7cf985be2c0639be28cc993ab30d8215373cab23d769991 xorg-x11-server-devel-1.20.4-34.el7_9.ppc64le.rpm SHA-256: 7bc3e7c9df67f4ef5a6d7b024ceb3f1348498baffe2041f8c7a5d4dcde63ee7e xorg-x11-server-source-1.20.4-34.el7_9.noarch.rpm SHA-256: 27e98b99ab2459357db2fe9156555923bdc1177d0d46cb8cc885ea0d09bebdd8 The Red Hat security contact is secalert@redhat.com . 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