ESB-2026.4055

=========================================================================== AUSCERT External Security Bulletin Redistribution ESB-2026.4055 kernel security update 22 April 2026 =========================================================================== AUSCERT Security Bulletin Summary --------------------------------- Product: kernel Publisher: Red Hat Operating System: Red Hat Resolution: Patch/Upgrade CVE Names: CVE-2026-23204 CVE-2026-23231 Original Bulletin: https://access.redhat.com/errata/RHSA-2026:9515 Comment: CVSS (Max): 7.5 CVE-2026-23231 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H) CVSS Source: Red Hat Calculator: https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H EPSS (Max): 0.0% (3rd) CVE-2026-23231 2026-04-21 - --------------------------BEGIN INCLUDED TEXT-------------------- RHSA-2026:9515 - Security Advisory Issued: 2026-04-22 Updated: 2026-04-22 Synopsis Kernel security update Type/Severity Security Advisory: Moderate 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): o kernel: net/sched: cls_u32: use skb_header_pointer_careful() (CVE-2026-23204) o 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 o Red Hat Enterprise Linux for x86_64 - Extended Update Support Extension 8.8 x86_64 o Red Hat Enterprise Linux Server - TUS 8.8 x86_64 o Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 8.8 ppc64le o Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 8.8 x86_64 Fixes o BZ - 2439931 - CVE-2026-23204 kernel: net/sched: cls_u32: use skb_header_pointer_careful() o BZ - 2444376 - CVE-2026-23231 kernel: kernel: Privilege escalation or denial of service via use-after-free in nf_tables_addchain() CVEs o CVE-2026-23204 o CVE-2026-23231 References o https://access.redhat.com/security/updates/classification/#moderate - --------------------------END INCLUDED TEXT---------------------- You have received this e-mail bulletin as a result of your organisation's registration with AUSCERT. The mailing list you are subscribed to is maintained within your organisation, so if you do not wish to continue receiving these bulletins you should contact your local IT manager. If you do not know who that is, please send an email to auscert@auscert.org.au and we will forward your request to the appropriate person. NOTE: Third Party Rights This security bulletin is provided as a service to AUSCERT's members. As AUSCERT did not write the document quoted above, AUSCERT has had no control over its content. The decision to follow or act on information or advice contained in this security bulletin is the responsibility of each user or organisation, and should be considered in accordance with your organisation's site policies and procedures. AUSCERT takes no responsibility for consequences which may arise from following or acting on information or advice contained in this security bulletin. NOTE: This is only the original release of the security bulletin. It may not be updated when updates to the original are made. If downloading at a later date, it is recommended that the bulletin is retrieved directly from the author's website to ensure that the information is still current. Contact information for the authors of the original document is included in the Security Bulletin above. If you have any questions or need further information, please contact them directly. Previous advisories and external security bulletins can be retrieved from: https://portal.auscert.org.au/bulletins/ =========================================================================== AUSCERT The University of Queensland, Brisbane QLD 4072 Australia e: auscert@auscert.org.au t: +61 (0)7 3365 4417 Allies in Cyber Security ===========================================================================