CVE-2023-53474: x86/MCE/AMD: Use an u64 for bank_map

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-01 · updated 2026-10-15
Weakness: CWE-190

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. ]

Affected products

Linux kernel: from 5.10 before 5.10.180; from 5.11 before 5.15.111; from 5.16 before 6.1.28; from 6.2 before 6.2.15; from 6.3 before 6.3.2 — fixed in 5.10.180, 5.15.111, 6.1.28, 6.2.15, 6.3.2

How to fix

Upgrade to a fixed version: Linux kernel 5.10.180, 5.15.111, 6.1.28, 6.2.15. Check the vendor advisory for mitigations.

References

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