Red Hat Product Errata RHSA-2026:38486 - Security Advisory Issued: 2026-07-13 Updated: 2026-07-13 RHSA-2026:38486 - 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. 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: xserver: X.org: glamor Font Atlas Heap Buffer Overflow (CVE-2026-55999) 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 x86_64 - Extended Update Support 9.8 x86_64 Red Hat Enterprise Linux for IBM z Systems 9 s390x Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.8 s390x Red Hat Enterprise Linux for Power, little endian 9 ppc64le Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.8 ppc64le Red Hat Enterprise Linux for ARM 64 9 aarch64 Red Hat Enterprise Linux for ARM 64 - Extended Update Support 9.8 aarch64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.8 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.8 x86_64 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 Red Hat CodeReady Linux Builder for x86_64 - Extended Update Support 9.8 x86_64 Red Hat CodeReady Linux Builder for Power, little endian - Extended Update Support 9.8 ppc64le Red Hat CodeReady Linux Builder for IBM z Systems - Extended Update Support 9.8 s390x Red Hat CodeReady Linux Builder for ARM 64 - Extended Update Support 9.8 aarch64 Red Hat Enterprise Linux for ARM 64 - 4 years of updates 9.8 aarch64 Red Hat Enterprise Linux for IBM z Systems - 4 years of updates 9.8 s390x Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.8 x86_64 Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle 9.8 aarch64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.8 ppc64le Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle 9.8 s390x Fixes BZ - 2496165 - CVE-2026-55999 xorg: X11: xserver: X.org: glamor Font Atlas Heap Buffer Overflow CVEs CVE-2026-55999 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-1.20.11-34.el9_8.3.src.rpm SHA-256: 125681b17559bd5fe9a61c12bf15620b53bef1b36452ee91ffffd6403ddec415 x86_64 xorg-x11-server-Xdmx-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 393f2cd835a68cc54d747cf815a87a9b03f000057de316f8f439ac022fb49675 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: fabef3a197d1ee084d2fc5fb304293dd18a97701430a67d199427b7b6852fdb4 xorg-x11-server-Xephyr-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: ba9d15a9d792c03aef5bf0dede47ca5c2a5945965d2f32c002ec32fc772421fa xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 32eb2de614f47dce2874f2f87b766a41cfdf46c2528da1da04b21ebcafbc6681 xorg-x11-server-Xnest-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 90a8783dc2ba8e96e2f8b820c8b7417e19f83e2a7ca7b75ccdde2a21d283cb49 xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 96d1824d497db13c0b593e997d4f6bdaa1a57dfc8a6e76e26a5d0f7cdfd66946 xorg-x11-server-Xorg-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: a55a17db6b3957e226a925038661bd727cf7300a7530596503131bd8178be0db xorg-x11-server-Xorg-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: e64fce436f3b895d9c05520357108423ffa3a5627a74006352aa1e9714bf8587 xorg-x11-server-Xvfb-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 2318f9578cad7e0ec87d728245b845ab82d898174d785ae9d00566ef78fa5bce xorg-x11-server-Xvfb-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 8b23bb60645465b66295777211d36b2970c363486bde81cb3922b953199e8849 xorg-x11-server-common-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 9a41442c0308edce11d8e190f1c08fea99dcf45ef1f8e49a5f0ef2900a2fa61b xorg-x11-server-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 3024ece7e5f861529c14a0e864bee5740c11edf0521d5456640264eb237c5298 xorg-x11-server-debugsource-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: a657db237aaea677a30ffc0b267ac09610951ee46c22ec09b571e2816fd93cf6 Red Hat Enterprise Linux for x86_64 - Extended Update Support 9.8 SRPM xorg-x11-server-1.20.11-34.el9_8.3.src.rpm SHA-256: 125681b17559bd5fe9a61c12bf15620b53bef1b36452ee91ffffd6403ddec415 x86_64 xorg-x11-server-Xdmx-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 393f2cd835a68cc54d747cf815a87a9b03f000057de316f8f439ac022fb49675 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: fabef3a197d1ee084d2fc5fb304293dd18a97701430a67d199427b7b6852fdb4 xorg-x11-server-Xephyr-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: ba9d15a9d792c03aef5bf0dede47ca5c2a5945965d2f32c002ec32fc772421fa xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 32eb2de614f47dce2874f2f87b766a41cfdf46c2528da1da04b21ebcafbc6681 xorg-x11-server-Xnest-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 90a8783dc2ba8e96e2f8b820c8b7417e19f83e2a7ca7b75ccdde2a21d283cb49 xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 96d1824d497db13c0b593e997d4f6bdaa1a57dfc8a6e76e26a5d0f7cdfd66946 xorg-x11-server-Xorg-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: a55a17db6b3957e226a925038661bd727cf7300a7530596503131bd8178be0db xorg-x11-server-Xorg-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: e64fce436f3b895d9c05520357108423ffa3a5627a74006352aa1e9714bf8587 xorg-x11-server-Xvfb-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 2318f9578cad7e0ec87d728245b845ab82d898174d785ae9d00566ef78fa5bce xorg-x11-server-Xvfb-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 8b23bb60645465b66295777211d36b2970c363486bde81cb3922b953199e8849 xorg-x11-server-common-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 9a41442c0308edce11d8e190f1c08fea99dcf45ef1f8e49a5f0ef2900a2fa61b xorg-x11-server-debuginfo-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: 3024ece7e5f861529c14a0e864bee5740c11edf0521d5456640264eb237c5298 xorg-x11-server-debugsource-1.20.11-34.el9_8.3.x86_64.rpm SHA-256: a657db237aaea677a30ffc0b267ac09610951ee46c22ec09b571e2816fd93cf6 Red Hat Enterprise Linux for IBM z Systems 9 SRPM xorg-x11-server-1.20.11-34.el9_8.3.src.rpm SHA-256: 125681b17559bd5fe9a61c12bf15620b53bef1b36452ee91ffffd6403ddec415 s390x xorg-x11-server-Xdmx-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 81997582a1bfbbc3ffa5d7a320aa7bcc8c11475b9249be1d86c343fcddfee8c8 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 38514b3b6ec5a39c4c22ec09c9937c4495569ce16a38be719d97ecb54b5240af xorg-x11-server-Xephyr-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 3bf4d972283e90efb234fc8d73fd8bac5680012b61b325a9259510106fcf2e8d xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 571c87bf2e301c32f8e48883851b55ecf7955e9553fc9de4131945e4d2f5e9e3 xorg-x11-server-Xnest-1.20.11-34.el9_8.3.s390x.rpm SHA-256: fcca36dd1f7c6edd109d49ca691706156f415548830f967c0d1ca41739bf5c60 xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 1cbb27eb03fe0268c98008e89140f1b83a49004cbe05b97b17e794a3cd81e80f xorg-x11-server-Xorg-1.20.11-34.el9_8.3.s390x.rpm SHA-256: ea0e65c80b38e42c15d60a013077917bc497900702a2813dc4e0dc6167836f13 xorg-x11-server-Xorg-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: efadb4cea414d34129c44a7c73861d9aacb6b030f922f371278ed27dec36fbf2 xorg-x11-server-Xvfb-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 754f041ff2057e907c9cb458ad74f653850dc0f3c1fabdeea064ad36d0fb695f xorg-x11-server-Xvfb-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 1f08b5d085f5545189690f05a191ee9fdbfcc64aa6c200a05c7c2524e691c500 xorg-x11-server-common-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 599e3cf6b03d1a2e162a8a4bd2f13576c1fe65bafb17da609e6ccd7891e9c14d xorg-x11-server-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 9de7ac1449ad07cf1f321d2d5efb5c3a20180d395aa3697e5adf88fdb835b665 xorg-x11-server-debugsource-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 396f9242b0250d51d1e0f4a7a2bdbfea8ec974dd735019f6ae3437e743fe16dd Red Hat Enterprise Linux for IBM z Systems - Extended Update Support 9.8 SRPM xorg-x11-server-1.20.11-34.el9_8.3.src.rpm SHA-256: 125681b17559bd5fe9a61c12bf15620b53bef1b36452ee91ffffd6403ddec415 s390x xorg-x11-server-Xdmx-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 81997582a1bfbbc3ffa5d7a320aa7bcc8c11475b9249be1d86c343fcddfee8c8 xorg-x11-server-Xdmx-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 38514b3b6ec5a39c4c22ec09c9937c4495569ce16a38be719d97ecb54b5240af xorg-x11-server-Xephyr-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 3bf4d972283e90efb234fc8d73fd8bac5680012b61b325a9259510106fcf2e8d xorg-x11-server-Xephyr-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 571c87bf2e301c32f8e48883851b55ecf7955e9553fc9de4131945e4d2f5e9e3 xorg-x11-server-Xnest-1.20.11-34.el9_8.3.s390x.rpm SHA-256: fcca36dd1f7c6edd109d49ca691706156f415548830f967c0d1ca41739bf5c60 xorg-x11-server-Xnest-debuginfo-1.20.11-34.el9_8.3.s390x.rpm SHA-256: 1cbb27eb03fe0268c98008e89140f1b83a49004cbe05b97b17e794a3cd81e80f xorg-x11-server-Xorg-1.20.11-34