In the Linux kernel, the following vulnerability has been resolved:
x86/MCE/AMD: Use an u64 for bank_map
Thee maximum number of MCA banks is 64 (MAX_NR_BANKS), see
a0bc32b3cacf ("x86/mce: Increase maximum number of banks to 64").
However, the bank_map which contains a bitfield of which banks to initialize is of type unsigned int and that overflows when those bit numbers are >= 32, leading to UBSAN complaining correctly:
UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/mce/amd.c:1365:38 shift exponent 32 is too large for 32-bit type 'int'
Change the bank_map to a u64 and use the proper BIT_ULL() macro when modifying bits in there.
[ bp: Rewrite commit message. ]
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Amazon Linux Ami 2 | — | Upgrade kernel-debuginfoUpgrade kernel-tools-debuginfoUpgrade kernel-tools-develUpgrade perfUpgrade perf-debuginfoUpgrade kernel-toolsUpgrade kernel-debuginfo-common-aarch64Upgrade bpftoolUpgrade kernel-livepatch-5.15.117-72.142Upgrade kernel-develUpgrade bpftool-debuginfoUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-livepatch-5.10.184-174.730Upgrade kernel-headersUpgrade python-perf-debuginfoUpgrade kernelUpgrade python-perf | May 20, 2026 | May 20, 2026 |
| Amazon_linux_2023 | — | Upgrade kernel-debuginfo-common-aarch64Upgrade python3-perfUpgrade kernel-tools-develUpgrade perfUpgrade perf-debuginfoUpgrade kernel-headersUpgrade kernel-tools-debuginfoUpgrade kernelUpgrade kernel-toolsUpgrade python3-perf-debuginfoUpgrade kernel-debuginfoUpgrade bpftool-debuginfoUpgrade kernel-livepatch-6.1.29-47.49Upgrade kernel-develUpgrade kernel-libbpf-develUpgrade kernel-libbpf-staticUpgrade bpftoolUpgrade kernel-debuginfo-common-x86_64Upgrade kernel-libbpf | Oct 16, 2025 | Oct 1, 2025 |
| Debian | — | Upgrade linux | Oct 3, 2025 | Oct 3, 2025 |
| Redhat_linux | — | No solution exists | Jul 17, 2026 | Oct 1, 2025 |
| Ubuntu | — | Upgrade linux-lowlatencyUpgrade linux-gkeUpgrade linux-ibm-5.15Upgrade linux-nvidia-tegra-5.15Upgrade linux-lowlatency-hwe-5.15Upgrade linux-oracle-5.15Upgrade linux-nvidia-tegraUpgrade linux-raspiUpgrade linux-riscv-5.15Upgrade linuxUpgrade linux-intel-iotgUpgrade linux-realtimeUpgrade linux-xilinx-zynqmpUpgrade linux-aws-5.15Upgrade linux-nvidiaUpgrade linux-gkeopUpgrade linux-azureUpgrade linux-intel-iot-realtimeUpgrade linux-intel-iotg-5.15Upgrade linux-awsUpgrade linux-gcp-5.15Upgrade linux-hwe-5.15Upgrade linux-bluefieldUpgrade linux-oracleUpgrade linux-gcpUpgrade linux-ibmUpgrade linux-kvmUpgrade linux-nvidia-tegra-igxUpgrade linux-azure-5.15 | Oct 10, 2025 | Oct 1, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Oct 15, 2025 | Oct 1, 2025 |
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