This Red Hat kernel security update addresses two vulnerabilities: CVE-2026-43499 (CVSS 7.8 HIGH) in the rtmutex subsystem and CVE-2026-53166 in the futex requeue mechanism, which could lead to NULL pointer dereferences and potential denial of service. The vulnerabilities affect a wide range of Linux kernel versions, specifically from 2.6.39 up to but excluding 6.1.175, 6.2 up to 6.6.140, 6.7 up to 6.12.86, 6.13 up to 6.18.27, and 6.19 up to 7.0.4. Red Hat has provided fixed packages for RHEL 8.4 ELS and AUS, requiring a system reboot for the update to take effect.
Red Hat Product Errata RHSA-2026:39984 - Security Advisory Issued: 2026-07-15 Updated: 2026-07-15 RHSA-2026:39984 - Security Advisory Overview Updated Packages Synopsis Important: kernel 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 kernel is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On. 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 The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): kernel: rtmutex: Use waiter::task instead of current in remove_waiter() (CVE-2026-43499) kernel: futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock (CVE-2026-53166) kernel: XFS data corruption using reflink () 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 The system must be rebooted for this update to take effect. Affected Products Red Hat Enterprise Linux for x86_64 - Extended Life Cycle Long Life 8.4 x86_64 Red Hat Enterprise Linux Server - AUS 8.4 x86_64 Fixes BZ - 2480453 - CVE-2026-43499 kernel: rtmutex: Use waiter::task instead of current in remove_waiter() BZ - 2492805 - CVE-2026-53166 kernel: futex/requeue: Prevent NULL pointer dereference in remove_waiter() on self-deadlock BZ - 2498915 - kernel: XFS data corruption using reflink CVEs CVE-2026-43499 CVE-2026-53166 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 - Extended Life Cycle Long Life 8.4 SRPM kernel-4.18.0-305.198.1.el8_4.src.rpm SHA-256: 360c6b8be5047c18ec5754010a07c65f8402a4f1e68446b8fc87cfdafc52e560 x86_64 bpftool-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 63fe459b49209be25c90ac63df66bb9615de7fa089f2c781227fdd69545fdca2 bpftool-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 9446328dbfe99eb3eb0904d5600b5b90470754fff04a8eecde7ccc82baaa21fb kernel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 39456b7e4e16c85a63754482907379b57d2f986b09a31342d0e0a2961f55cca8 kernel-abi-stablelists-4.18.0-305.198.1.el8_4.noarch.rpm SHA-256: 6b03abe9d1c9bb46b72cf39d3f44a66da12721f4e55daeab9c52122088fe7cae kernel-core-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 77686c7ea7df8dfd6f987298ee64759c9fff415f2b0ab7a8ae502d0464ae1169 kernel-cross-headers-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 849f1d1a150753b8860c2f85ae337bff38bfa2bfefd9513299bece41a54f0cf7 kernel-debug-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 6e37bd7d35aa931f2eca5a71bed58bc557773ce634103e1c2ee5309ee88b3635 kernel-debug-core-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: b770bea0e761574cc7b89a0e0b61c53d02ac4114e85b8c93f1fcd56f86687519 kernel-debug-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 282e4fdacbbfd41300afe9c0c4b3163ce1689268ff13668dafbaf03139aed751 kernel-debug-devel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 891e2432d308253d4776723369d4a9e0f578c98721fd5daa1071d06771bbfadd kernel-debug-modules-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 7d6685a2a24f6b2e70ab31bbfca64faad05e09db7cce8952fa2d32d7b4c08704 kernel-debug-modules-extra-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: d67d8ad65491dc95e26fe60d4001700de596d5d84dbca11a503040e4846a6ce3 kernel-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 646d66e688dd6b40e367ee43d9edaddf78ae849b440e0a7c66d52f81a997abb4 kernel-debuginfo-common-x86_64-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 6f4647e189ffd88e282a90c4b96e27a68b313a7d0b96af4f5ad1f2362f3c2f90 kernel-devel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: cd53244cc225b1b022eabb2cf72597bed0976ed20d1db4c747c2fb81559e3b44 kernel-doc-4.18.0-305.198.1.el8_4.noarch.rpm SHA-256: 0390b603ff3755468fd10458ebc0df113d10b33532eccb48a71476842f8cdd44 kernel-headers-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 0aebad42ea15af9d4c43dfa24b002dda833bbc40a0c63e8e66c7095b5b2ca3c9 kernel-modules-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: cca07b86505ce5b3afeeb8a291bc70d003eb7ede6532d268a569156916b91ba0 kernel-modules-extra-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: c9910fc4aacc299d7176e1fdd95f08b1cbd51bc006cd90be57d7298ea598967f kernel-tools-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 80973a15396330b05b0b0604637e3a03c1389de541e8b96ca95de357fd92d7d7 kernel-tools-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 93daa299cbd8163ecd6c80da288ee99bc106f62a0919f1c83c4281ed285124db kernel-tools-libs-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 0f94bda9be9747e7d5b940b8ba8aaf4601be7e70913804a1c0ebf3216ab7a002 perf-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 01ceb4b338f0e064dac5e3cc89157aaa557f29fbfd164aef91b26e90b83d78ec perf-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: b1c3e66afbc371fb9b953aef0e241d4ba81e5979d648f318e9705189252fc05e python3-perf-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: d181b1e53c91e84d6ab99b0c8bc2cd76d1466eb9f63c7f631bddf47352e5e376 python3-perf-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: dd4d66d6692c244062eff6f0ba793dab5888ea69acfb3ede715fe6a21dab00ae Red Hat Enterprise Linux Server - AUS 8.4 SRPM kernel-4.18.0-305.198.1.el8_4.src.rpm SHA-256: 360c6b8be5047c18ec5754010a07c65f8402a4f1e68446b8fc87cfdafc52e560 x86_64 bpftool-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 63fe459b49209be25c90ac63df66bb9615de7fa089f2c781227fdd69545fdca2 bpftool-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 9446328dbfe99eb3eb0904d5600b5b90470754fff04a8eecde7ccc82baaa21fb kernel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 39456b7e4e16c85a63754482907379b57d2f986b09a31342d0e0a2961f55cca8 kernel-abi-stablelists-4.18.0-305.198.1.el8_4.noarch.rpm SHA-256: 6b03abe9d1c9bb46b72cf39d3f44a66da12721f4e55daeab9c52122088fe7cae kernel-core-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 77686c7ea7df8dfd6f987298ee64759c9fff415f2b0ab7a8ae502d0464ae1169 kernel-cross-headers-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 849f1d1a150753b8860c2f85ae337bff38bfa2bfefd9513299bece41a54f0cf7 kernel-debug-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 6e37bd7d35aa931f2eca5a71bed58bc557773ce634103e1c2ee5309ee88b3635 kernel-debug-core-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: b770bea0e761574cc7b89a0e0b61c53d02ac4114e85b8c93f1fcd56f86687519 kernel-debug-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 282e4fdacbbfd41300afe9c0c4b3163ce1689268ff13668dafbaf03139aed751 kernel-debug-devel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 891e2432d308253d4776723369d4a9e0f578c98721fd5daa1071d06771bbfadd kernel-debug-modules-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 7d6685a2a24f6b2e70ab31bbfca64faad05e09db7cce8952fa2d32d7b4c08704 kernel-debug-modules-extra-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: d67d8ad65491dc95e26fe60d4001700de596d5d84dbca11a503040e4846a6ce3 kernel-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 646d66e688dd6b40e367ee43d9edaddf78ae849b440e0a7c66d52f81a997abb4 kernel-debuginfo-common-x86_64-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 6f4647e189ffd88e282a90c4b96e27a68b313a7d0b96af4f5ad1f2362f3c2f90 kernel-devel-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: cd53244cc225b1b022eabb2cf72597bed0976ed20d1db4c747c2fb81559e3b44 kernel-doc-4.18.0-305.198.1.el8_4.noarch.rpm SHA-256: 0390b603ff3755468fd10458ebc0df113d10b33532eccb48a71476842f8cdd44 kernel-headers-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 0aebad42ea15af9d4c43dfa24b002dda833bbc40a0c63e8e66c7095b5b2ca3c9 kernel-modules-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: cca07b86505ce5b3afeeb8a291bc70d003eb7ede6532d268a569156916b91ba0 kernel-modules-extra-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: c9910fc4aacc299d7176e1fdd95f08b1cbd51bc006cd90be57d7298ea598967f kernel-tools-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 80973a15396330b05b0b0604637e3a03c1389de541e8b96ca95de357fd92d7d7 kernel-tools-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 93daa299cbd8163ecd6c80da288ee99bc106f62a0919f1c83c4281ed285124db kernel-tools-libs-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 0f94bda9be9747e7d5b940b8ba8aaf4601be7e70913804a1c0ebf3216ab7a002 perf-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: 01ceb4b338f0e064dac5e3cc89157aaa557f29fbfd164aef91b26e90b83d78ec perf-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: b1c3e66afbc371fb9b953aef0e241d4ba81e5979d648f318e9705189252fc05e python3-perf-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: d181b1e53c91e84d6ab99b0c8bc2cd76d1466eb9f63c7f631bddf47352e5e376 python3-perf-debuginfo-4.18.0-305.198.1.el8_4.x86_64.rpm SHA-256: dd4d66d6692c244062eff6f0ba793dab5888ea69acfb3ede715fe6a21dab00ae The Red Hat security contact is secalert@redhat.com . 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