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Kernel Security Update — AlmaLinux 10 (ALSA-2026:91565)

ALSA-2026:91565 updates the AlmaLinux 10 kernel, fixing sixteen vulnerabilities (CVE-2026-53236, CVE-2026-53388, CVE-2026-64027, CVE-2026-63979, CVE-2026-63978, CVE-2026-64109, CVE-2026-64523, CVE-2026-68136, CVE-2026-68338, CVE-2026-72083, CVE-2026-74515, CVE-2026-74631, CVE-2026-80824, CVE-2026-89638, CVE-2026-89777 and CVE-2026-93262) — including a tcp SO_ATTACH_FILTER restriction for privileged users and a fuse page-cache folio locking fix. Aggregate CVSS 5.5; update the kernel and reboot.

High 5.5 CVSS
AlmaLinux 10

What this means under a SharedLicense license

Networking and filesystem kernel flaws (tcp filter handling, fuse page-cache locking) are reachable through local and, in some cases, crafted network states — unpatched, they expose the host to crashes and local escalation attempts.

The kernel packages contain the Linux kernel, the core of any Linux operating system.  

Security Fix(es):  

  * kernel: tcp: restrict SO_ATTACH_FILTER to priv users (CVE-2026-53236)
  * kernel: fuse: re-lock request before replacing page cache folio (CVE-2026-53388)
  * kernel: net: shaper: rework the VALID marking (again) (CVE-2026-64027)
  * kernel: net/handshake: hand off the pinned file reference to accept_doit (CVE-2026-63979)
  * kernel: net/handshake: Drain pending requests at net namespace exit (CVE-2026-63978)
  * kernel: af_unix: Fix UAF read of tail->len in unix_stream_data_wait() (CVE-2026-64109)
  * kernel: net/handshake: Take a long-lived file reference at submit (CVE-2026-64523)
  * kernel: net: gro: fix double aggregation of flush-marked skbs (CVE-2026-68136)
  * kernel: net/packet: avoid fanout hook re-registration after unregister (CVE-2026-68338)
  * kernel: scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE (CVE-2026-72083)
  * kernel: KVM: s390: pci: Reject adapter interrupt forwarding if already enabled (CVE-2026-74515)
  * kernel: net: smc: fix splice entry lifetime imbalance in smc_rx_splice (CVE-2026-74631)
  * kernel: usb: usbfs: fix use-after-free of usb_device in usbdev_release() (CVE-2026-80824)
  * kernel: smb: client: clear setuid/setgid bit on write with cifsacl/modefromsid/posix extensions (CVE-2026-89638)
  * kernel: vfio/pci: clear vdev->msi_perm after freeing it on init failure (CVE-2026-89777)
  * kernel: md/raid5-ppl: fix use-after-free in ppl_do_flush() (CVE-2026-93262)


Bug Fix(es) and Enhancement(s):  

  * x86/microcode: Add platform mask to Intel microcode "old" list [AlmaLinux-10] [almalinux-10.2.z] (JIRA:AlmaLinux-212778)
  * net: NULL pointer deref kernel panic in fib6_walk_continue under heavy VRF churn [almalinux-10.2.z] (JIRA:AlmaLinux-245489)
  * backport fixes for lockdep issues reported with rt-debug [almalinux-10.2.z] (JIRA:AlmaLinux-259937)


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.

Frequently Asked Questions

What is ALSA-2026:91565?
It is AlmaLinux's kernel erratum for AlmaLinux 10, updating the kernel with fixes for sixteen CVEs including CVE-2026-53236 (tcp: restrict SO_ATTACH_FILTER to privileged users) and CVE-2026-53388 (fuse: re-lock request before replacing page cache folio). Aggregate CVSS 5.5 — routine but important kernel maintenance.
How do I apply the update?
Run dnf update kernel kernel-modules kernel-modules-extra and reboot into the new kernel — kernel fixes require a restart. Verify with uname -r reporting the erratum's build.
Are these kernel flaws severe?
Individually moderate (aggregate 5.5), but the batch includes networking and filesystem handling fixes — the tcp SO_ATTACH_FILTER restriction in particular closes a filter-attachment path that was previously available to unprivileged users.
Is a reboot really required?
Yes — the running kernel is loaded in memory at boot; package updates alone do not protect a running server. The only alternative is KernelCare live patching if it covers these CVEs (verify with kcarectl --patch-info).

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