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: linux kernel
References6
- git.kernel.org/stable/c/11c58a0c1937c157dbdf82d5ab634d68c99f3098 Patch
- git.kernel.org/stable/c/4c1cdec319b9aadb65737c3eb1f5cb74bd6aa156 Patch
- git.kernel.org/stable/c/67bb7521b6420d81dab7538c0686f18f7d6d09f4 Patch
- git.kernel.org/stable/c/9669fa17287c3af2bbd4868d4c8fdd9e57f8332e Patch
- git.kernel.org/stable/c/a9b9ea0e63a0ec5e97bf1219ab6dcbd55e362f83 Patch
- git.kernel.org/stable/c/ba8ffb1251eb629c2ec35220e3896cf4f7b888a7 Patch
Metrics
- CVSS 3.1
-
5.5
MEDIUM
Score source: NVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 6 · as of 9 November 2026
- CWE
- CWE-190
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.