Red Hat Product Errata RHSA-2026:9515 - Security Advisory Issued: 2026-04-22 Updated: 2026-04-22 RHSA-2026:9515 - Security Advisory Overview Updated Packages Synopsis Moderate: kernel security update Type/Severity Security Advisory: Moderate 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 8.8 Update Services for SAP Solutions and Red Hat Enterprise Linux 8.8 Telecommunications Update Service. Red Hat Product Security has rated this update as having a security impact of Moderate. 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: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() (CVE-2026-23231) 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 Update Support Extension 8.8 x86_64 Red Hat Enterprise Linux Server - TUS 8.8 x86_64 Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 8.8 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 8.8 x86_64 Fixes BZ - 2439931 - CVE-2026-23204 kernel: net/sched: cls_u32: use skb_header_pointer_careful() BZ - 2444376 - CVE-2026-23231 kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() CVEs CVE-2026-23204 CVE-2026-23231 References https://access.redhat.com/security/updates/classification/#moderate 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 Update Support Extension 8.8 SRPM kernel-4.18.0-477.136.1.el8_8.src.rpm SHA-256: 7eeb2e1e34e1ae1bf6717c5cdadf4fd16674c11828c1e27b1ced9df650148829 x86_64 bpftool-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: de6427febcc2a049bbf907b3be86bbfd24ad1e08dab7982ace655a138db42ee1 bpftool-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: e1fd76493a9e88b1ad7a6bee3052cc4bce49edd5568718e4a53f82ad6b24cf2e kernel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 35a2491ffa2d88ddce794318422451f50dc17ee1a7c155eb8767d987b016ab31 kernel-abi-stablelists-4.18.0-477.136.1.el8_8.noarch.rpm SHA-256: 73cce08677e7adf88e3d200ce0291e1373cd36398ce45f0a6f0296d0f86cf12a kernel-core-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 52a38eccb58077fbf030883cabaa35fe187a8b74e0c9198d72158bee0a390c91 kernel-cross-headers-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c55c782f89ae1151d5a39d1e485fae1c991e24e929c8d447a965030780783bc9 kernel-debug-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 735c4f6555980a53e58e3cf66678c8f056a67521c65c3bb9a16a27da44ab2983 kernel-debug-core-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2b18c12ca73544c3915c84d6dbd1a49c98bbf79d862bda05c4ae59c5ef964d06 kernel-debug-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: b6af409c7c9bee7dce261bbeedd1b796dbc81a90909a8505e62229da11242a55 kernel-debug-devel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2f5da9de413fa2dcdfb562dc41ae399bef06f12b91e985e691b52c60965e88b1 kernel-debug-modules-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 995abd036b23bd2fe3eec015f89868d54b64201f9c4151bbe48ae35f9e72fc44 kernel-debug-modules-extra-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 72779a4443371dff3dc8120ab4191432ecae17d68584a6a956db9112675a47c3 kernel-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 40001521e672bd7a9f6879202085bb967a2856bdfd15bf0cee2d4c1282eacf76 kernel-debuginfo-common-x86_64-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: d5edae962277694953a82b2d576919fa1dc036208ce9eaa86eee9b382d74e08e kernel-devel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 251992e671c8d8e5b6de833d9176dc3e74424bf255db5734bbbb59ff0f486a59 kernel-doc-4.18.0-477.136.1.el8_8.noarch.rpm SHA-256: 8b5df5b309d2dc16cde2352e8be677484e7c6ab171d660c0b944175d3a7ab51d kernel-headers-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: ab5e782c0c93e50613874dcb9026604085357edc049f50e52c271e44208b41cd kernel-modules-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 44084cb3352e525390189f7ec625429d01a951702e7f54e9595f704e41d42a30 kernel-modules-extra-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c8c56139d3798ba572e3877e0d2bc7c0d8a16700ae8b7224ac5f22b016fa7521 kernel-tools-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2f7cc92485e595c9db6b6f7512f5e6890e64dad432a337f7ffd1cce4f1856006 kernel-tools-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c121c9fc91c63b150b2480dcb9544f0178adf3fa19f31880e6dd653d95c0c5a6 kernel-tools-libs-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 22cfdcef2b141ba0e1a2aa2c3e08997ae02465b699d39c16c4ae95c712c78167 perf-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 3db23bed6aed6318ca65c3f5c2ab896c56a9acd077b417687f28e49e2e710354 perf-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 51627b1ab31cc6c4ecdd63cf9f631a208dd14ff879c1c789cd17cf4d4d72e1e4 python3-perf-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: be3a5bf01f11fd0c4da9258734e9ae3f6cbe2974e57f7d3679399d991238f407 python3-perf-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 48f59c3f43805dcf6b079235865e3e4fd96b0e464de862a0aee536f899c43abf Red Hat Enterprise Linux Server - TUS 8.8 SRPM kernel-4.18.0-477.136.1.el8_8.src.rpm SHA-256: 7eeb2e1e34e1ae1bf6717c5cdadf4fd16674c11828c1e27b1ced9df650148829 x86_64 bpftool-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: de6427febcc2a049bbf907b3be86bbfd24ad1e08dab7982ace655a138db42ee1 bpftool-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: e1fd76493a9e88b1ad7a6bee3052cc4bce49edd5568718e4a53f82ad6b24cf2e kernel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 35a2491ffa2d88ddce794318422451f50dc17ee1a7c155eb8767d987b016ab31 kernel-abi-stablelists-4.18.0-477.136.1.el8_8.noarch.rpm SHA-256: 73cce08677e7adf88e3d200ce0291e1373cd36398ce45f0a6f0296d0f86cf12a kernel-core-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 52a38eccb58077fbf030883cabaa35fe187a8b74e0c9198d72158bee0a390c91 kernel-cross-headers-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c55c782f89ae1151d5a39d1e485fae1c991e24e929c8d447a965030780783bc9 kernel-debug-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 735c4f6555980a53e58e3cf66678c8f056a67521c65c3bb9a16a27da44ab2983 kernel-debug-core-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2b18c12ca73544c3915c84d6dbd1a49c98bbf79d862bda05c4ae59c5ef964d06 kernel-debug-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: b6af409c7c9bee7dce261bbeedd1b796dbc81a90909a8505e62229da11242a55 kernel-debug-devel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2f5da9de413fa2dcdfb562dc41ae399bef06f12b91e985e691b52c60965e88b1 kernel-debug-modules-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 995abd036b23bd2fe3eec015f89868d54b64201f9c4151bbe48ae35f9e72fc44 kernel-debug-modules-extra-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 72779a4443371dff3dc8120ab4191432ecae17d68584a6a956db9112675a47c3 kernel-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 40001521e672bd7a9f6879202085bb967a2856bdfd15bf0cee2d4c1282eacf76 kernel-debuginfo-common-x86_64-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: d5edae962277694953a82b2d576919fa1dc036208ce9eaa86eee9b382d74e08e kernel-devel-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 251992e671c8d8e5b6de833d9176dc3e74424bf255db5734bbbb59ff0f486a59 kernel-doc-4.18.0-477.136.1.el8_8.noarch.rpm SHA-256: 8b5df5b309d2dc16cde2352e8be677484e7c6ab171d660c0b944175d3a7ab51d kernel-headers-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: ab5e782c0c93e50613874dcb9026604085357edc049f50e52c271e44208b41cd kernel-modules-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 44084cb3352e525390189f7ec625429d01a951702e7f54e9595f704e41d42a30 kernel-modules-extra-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c8c56139d3798ba572e3877e0d2bc7c0d8a16700ae8b7224ac5f22b016fa7521 kernel-tools-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 2f7cc92485e595c9db6b6f7512f5e6890e64dad432a337f7ffd1cce4f1856006 kernel-tools-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: c121c9fc91c63b150b2480dcb9544f0178adf3fa19f31880e6dd653d95c0c5a6 kernel-tools-libs-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 22cfdcef2b141ba0e1a2aa2c3e08997ae02465b699d39c16c4ae95c712c78167 perf-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 3db23bed6aed6318ca65c3f5c2ab896c56a9acd077b417687f28e49e2e710354 perf-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 51627b1ab31cc6c4ecdd63cf9f631a208dd14ff879c1c789cd17cf4d4d72e1e4 python3-perf-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: be3a5bf01f11fd0c4da9258734e9ae3f6cbe2974e57f7d3679399d991238f407 python3-perf-debuginfo-4.18.0-477.136.1.el8_8.x86_64.rpm SHA-256: 48f59c3f43805dcf6b079235865e3e4fd96b0e464de862a0aee536f899c43abf Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 8.8 SRPM kernel-4.18.0-477.136.1.el8_8.src.rpm SHA-256: 7eeb2e1e34e1ae1bf6717c5cdadf4fd16674c11828c1e27b1ced9df650148829 ppc64le bpftool-4.18.0-477.136.1.el8_8.ppc64le.rpm SHA-256: 86373c812f80646755c261272d15b5dc49f840ea265b5bc1279dbd711bc7d33c bpftool-debuginfo-4.18.0-477.136.1.el8_8.ppc64le.rpm SHA-256: 423b872c0cfaeeff11455bbcce62058758f8303baadccf8b8752a612fb17d533 kernel-4.18.0-477.136.1.el8_8.ppc64le.rpm SHA-256: 26ab2cf80f0bab13123fcedeb99bb61b4e12a9da2dc5b967f584fd43941c4a33 kernel-abi-stablelists-4.18.0-477.136.1.el8_8.noarch.rpm SHA-256: 73cce08677e7adf88e3d200ce0291e1373cd36398ce45f0a6f0296d0f86cf12a kernel-core-4.18.0-477.136.1.el8_8.ppc64le.rpm SHA-256: 792979f1373556e041ab061985212faec822f0ff475e63b9e988d75a6decd0b2 kernel-cross-header