Red Hat alert RHSA-2026:21556-01 (kernel) [LWN.net]

An update for kernel 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. The kernel packages contain the Linux kernel, the core of any Linux operating system. Security Fix(es): * kernel: proc: use the same treatment to check proc_lseek as ones for proc_read_iter et.al (CVE-2025-38653) * kernel: ima: don't clear IMA_DIGSIG flag when setting or removing non-IMA xattr (CVE-2025-68183) * kernel: nbd: defer config unlock in nbd_genl_connect (CVE-2025-68366) * kernel: crypto: asymmetric_keys - prevent overflow in asymmetric_key_generate_id (CVE-2025-68724) * kernel: iommu: disable SVA when CONFIG_X86 is set (CVE-2025-71089) * kernel: netfilter: nf_tables: release flowtable after rcu grace period on error (CVE-2026-23392) * kernel: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() (CVE-2026-23455) * kernel: Bluetooth: SCO: Fix use-after-free in sco_recv_frame() due to missing sock_hold (CVE-2026-31408) * kernel: net: sched: act_csum: validate nested VLAN headers (CVE-2026-31684) * kernel: netfilter: ip6t_eui64: reject invalid MAC header for all packets (CVE-2026-31685) * kernel: netfilter: nf_conntrack_helper: pass helper to expect cleanup (CVE-2026-43027) * kernel: Bluetooth: MGMT: validate LTK enc_size on load (CVE-2026-43020) * kernel: HID: wacom: fix out-of-bounds read in wacom_intuos_bt_irq (CVE-2026-43051) * kernel: smb: client: validate the whole DACL before rewriting it in cifsacl (CVE-2026-31709) * kernel: Bluetooth: SCO: fix race conditions in sco_sock_connect() (CVE-2026-43023) * kernel: wifi: brcmfmac: validate bsscfg indices in IF events (CVE-2026-43110) * kernel: netfilter: xt_tcpmss: check remaining length before reading optlen (CVE-2026-43190) * kernel: xfs: fix freemap adjustments when adding xattrs to leaf blocks (CVE-2026-43158) * kernel: mm/page_alloc: clear page->private in free_pages_prepare() (CVE-2026-43303) 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. This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

Original: https://access.redhat.com/security/data/csaf/v2/advisories/2026/rhsa-2026_21556.json