A critical vulnerability (CVE-2026-43037, CVSS 9.8) in the Linux kernel's ip6_tunnel module allows for potential exploitation due to a failure to clear the skb2->cb[] buffer in the ip4ip6_err() function. The vulnerability affects a wide range of kernel versions, specifically from 2.6.22 through 5.10.252, 5.11 through 5.15.202, 5.16 through 6.1.167, 6.2 through 6.6.133, and 6.7 through 6.12.80. Red Hat has issued critical live patch updates for its Enterprise Linux 9.6 Extended Update Support kernels to mitigate the issue.
Red Hat Product Errata RHSA-2026:28740 - Security Advisory Issued: 2026-06-24 Updated: 2026-06-24 RHSA-2026:28740 - Security Advisory Overview Updated Packages Synopsis Critical: kpatch-patch-5_14_0-570_116_1, kpatch-patch-5_14_0-570_17_1, kpatch-patch-5_14_0-570_39_1, kpatch-patch-5_14_0-570_66_1, and kpatch-patch-5_14_0-570_94_1 security update Type/Severity Security Advisory: Critical Red Hat Lightspeed patch analysis Identify and remediate systems affected by this advisory. View affected systems Topic An update for multiple packages is now available for Red Hat Enterprise Linux 9.6 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Critical. 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 This is a kernel live patch module which can be loaded by the kpatch command line utility to modify the code of a running kernel. This patch module is targeted for kernel-5.14.0-570.17.1.el9_6. Security Fix(es): kernel: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() (CVE-2026-43037) 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 - Extended Update Support 9.6 x86_64 Red Hat Enterprise Linux Server - AUS 9.6 x86_64 Red Hat Enterprise Linux for Power, little endian - Extended Update Support 9.6 ppc64le Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions 9.6 ppc64le Red Hat Enterprise Linux for x86_64 - Update Services for SAP Solutions 9.6 x86_64 Red Hat Enterprise Linux for x86_64 - Extended Life Cycle 9.6 x86_64 Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle 9.6 ppc64le Fixes BZ - 2464351 - CVE-2026-43037 kernel: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() CVEs CVE-2026-43037 References https://access.redhat.com/security/updates/classification/#critical Note: More recent versions of these packages may be available. Click a package name for more details. 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