RHSA-2026:3634 - Security Advisory

Topic

An update for kernel-rt is now available for Red Hat Enterprise Linux 7 Extended Lifecycle Support.

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.

Description

The kernel-rt packages provide the Real Time Linux Kernel, which enables fine-tuning for systems with extremely high determinism requirements.

Security Fix(es):

• kernel: Linux kernel: Memory corruption in Squashfs due to incorrect block size calculation (CVE-2025-38415)
• kernel: Linux kernel: Denial of Service in ATM CLIP module via infinite recursion (CVE-2025-38459)
• kernel: Linux kernel: Denial of Service via out-of-bounds read in USB configuration parsing (CVE-2025-39760)
• kernel: efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare (CVE-2025-39817)
• kernel: media: rc: fix races with imon_disconnect() (CVE-2025-39993)
• kernel: Linux kernel: Use-after-free in proc_readdir_de() can lead to privilege escalation or denial of service. (CVE-2025-40271)
• kernel: ext4: fix use-after-free in ext4_orphan_cleanup (CVE-2022-50673)
• kernel: NFSv4/pNFS: Clear NFS_INO_LAYOUTCOMMIT in pnfs_mark_layout_stateid_invalid (CVE-2025-68349)
• kernel: Linux kernel: Use-after-free in teql queueing discipline can lead to privilege escalation (CVE-2026-23074)

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 Real Time for x86_64 - Extended Life Cycle Support 7 x86_64

Fixes

• BZ - 2383404 - CVE-2025-38415 kernel: Linux kernel: Memory corruption in Squashfs due to incorrect block size calculation
• BZ - 2383487 - CVE-2025-38459 kernel: Linux kernel: Denial of Service in ATM CLIP module via infinite recursion
• BZ - 2394601 - CVE-2025-39760 kernel: Linux kernel: Denial of Service via out-of-bounds read in USB configuration parsing
• BZ - 2395805 - CVE-2025-39817 kernel: efivarfs: Fix slab-out-of-bounds in efivarfs_d_compare
• BZ - 2404121 - CVE-2025-39993 kernel: media: rc: fix races with imon_disconnect()
• BZ - 2419837 - CVE-2025-40271 kernel: Linux kernel: Use-after-free in proc_readdir_de() can lead to privilege escalation or denial of service.
• BZ - 2420347 - CVE-2022-50673 kernel: ext4: fix use-after-free in ext4_orphan_cleanup
• BZ - 2424880 - CVE-2025-68349 kernel: NFSv4/pNFS: Clear NFS_INO_LAYOUTCOMMIT in pnfs_mark_layout_stateid_invalid
• BZ - 2436791 - CVE-2026-23074 kernel: Linux kernel: Use-after-free in teql queueing discipline can lead to privilege escalation

CVEs

• CVE-2022-50673
• CVE-2025-38415
• CVE-2025-38459
• CVE-2025-39760
• CVE-2025-39817
• CVE-2025-39993
• CVE-2025-40271
• CVE-2025-68349
• CVE-2026-23074

References

• https://access.redhat.com/security/updates/classification/#important