SB2026073002 - Red Hat Enterprise Linux 9 update for kernel
Published: July 30, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 3 vulnerabilities.
1) Resource management error (CVE-ID: CVE-2025-40026)
CWE-ID: CWE-399 - Resource Management Errors
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to perform a denial of service (DoS) attack.
The vulnerability exists due to resource management error within the emulator_is_smm() and x86_emulate_instruction() functions in arch/x86/kvm/x86.c. A local user can perform a denial of service (DoS) attack.
2) Double free (CVE-ID: CVE-2026-31787)
CWE-ID: CWE-415 - Double Free
CVSSv4: 8.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N]
The vulnerability allows a local privileged user to circumvent kernel lockdown restrictions.
The vulnerability exists due to double free in the Linux kernel privcmd driver when handling privcmd operations. A local privileged user can trigger a double free of kernel memory to circumvent kernel lockdown restrictions.
Only Linux PVH or HVM domains booted in secure mode are affected; PV domains and non-Linux domains are not vulnerable.
3) Use-after-free (CVE-ID: CVE-2026-52923)
CWE-ID: CWE-416 - Use After Free
CVSSv4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in ipc_idr_alloc() in the checkpoint/restore SysV IPC allocation path when processing a request for the next SysV IPC id. A local user can request allocation beyond the valid IPC id range to cause a denial of service.
A subsequent walk of /proc/sysvipc/shm can dereference freed memory through a stale IDR entry.
Remediation
Install update from vendor's website.