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. ]
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Thu, 02 Oct 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Wed, 01 Oct 2025 12:00:00 +0000

Type Values Removed Values Added
Description 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. ]
Title x86/MCE/AMD: Use an u64 for bank_map
References

cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-01T11:42:43.798Z

Reserved: 2025-10-01T11:39:39.401Z

Link: CVE-2023-53474

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2025-10-01T12:15:49.687

Modified: 2025-10-01T12:15:49.687

Link: CVE-2023-53474

cve-icon Redhat

Severity : Important

Publid Date: 2025-10-01T00:00:00Z

Links: CVE-2023-53474 - Bugzilla

cve-icon OpenCVE Enrichment

No data.