{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2023-53474","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-10-01T11:39:39.401Z","datePublished":"2025-10-01T11:42:43.798Z","dateUpdated":"2026-08-05T09:14:15.723Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T09:14:15.723Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/MCE/AMD: Use an u64 for bank_map\n\nThee maximum number of MCA banks is 64 (MAX_NR_BANKS), see\n\n  a0bc32b3cacf (\"x86/mce: Increase maximum number of banks to 64\").\n\nHowever, the bank_map which contains a bitfield of which banks to\ninitialize is of type unsigned int and that overflows when those bit\nnumbers are >= 32, leading to UBSAN complaining correctly:\n\n  UBSAN: shift-out-of-bounds in arch/x86/kernel/cpu/mce/amd.c:1365:38\n  shift exponent 32 is too large for 32-bit type 'int'\n\nChange the bank_map to a u64 and use the proper BIT_ULL() macro when\nmodifying bits in there.\n\n  [ bp: Rewrite commit message. ]"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The affected code is x86 AMD machine-check bank initialization, reached only during local CPU identification and the CPU-hotplug online callback (`mce_cpu_online()`), plus the local threshold sysfs/LVT interrupt paths. There is no network-facing or adjacent-network path, and KVM caps guests at 32 MCA banks so the condition is not reachable from a guest.\nAC:L - On an affected system (AMD CPU whose MCG_CAP reports more than 32 MCA banks, as MAX_NR_BANKS=64 was raised to support), the out-of-range shift is hit deterministically on every CPU bring-up with no race, timing window, or memory-layout dependency. Consistent with the scoring of other hardware-model-specific arch/x86/kernel/cpu defects, the platform precondition is treated as the vulnerable configuration rather than as added complexity.\nPR:L - The buggy bitmap handling executes during boot with no privileges at all, and the misprogrammed threshold banks/MSR addresses it produces are subsequently exercised through the low-privilege local surface; re-triggering it deliberately via CPU offline/online needs only local access to the machine. A basic local user is the lowest-privileged actor on such a system, so PR:L rather than PR:H.\nUI:N - The defect is triggered automatically by kernel CPU initialization and the hotplug/thresholding paths; no victim has to open a file, mount anything, or take any other action.\nS:U - The corruption is confined to the kernel's own per-CPU MCE bookkeeping and MSR programming within the same security authority. No VM, IOMMU, or sandbox boundary is crossed — the KVM MCE bank limit of 32 rules out a guest-to-host angle.\nC:H - The aliased `smca_misc_banks_map` makes `smca_get_block_address()` hand back MISCy MSR addresses for banks that have no such registers, and `allocate_threshold_blocks()` recurses over and reads those out-of-range MCA register addresses, exposing hardware state that belongs to unrelated banks through the threshold block objects. Undefined shift behaviour additionally lets the compiler assume `bank < 32`, so the resulting indexing is not reliably bounded.\nI:H - `threshold_restart_bank()` performs an unguarded `wrmsr()` on the mis-derived `b->address`, so MCA threshold, LVT-offset and control registers of the wrong bank get overwritten, and the aliased `bank_map` enables/disables thresholding and deferred-error reporting for banks other than the intended ones. This is attacker-influenceable kernel-controlled machine state written to the wrong target.\nA:H - The same mis-derived address reaches the unguarded `rdmsr()`/`wrmsr()` in `threshold_restart_bank()`, where a non-existent MSR raises an unhandled `#GP` in kernel context and panics the machine, and with `CONFIG_UBSAN_TRAP=y` the shift-out-of-bounds itself traps during CPU bring-up. Beyond the crash, the corrupted `bank_map` breaks MCA thresholding for banks ≥32 so genuine uncorrectable hardware errors are misconfigured or unhandled."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kernel/cpu/mce/amd.c"],"versions":[{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"a9b9ea0e63a0ec5e97bf1219ab6dcbd55e362f83","status":"affected","versionType":"git"},{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"11c58a0c1937c157dbdf82d5ab634d68c99f3098","status":"affected","versionType":"git"},{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"ba8ffb1251eb629c2ec35220e3896cf4f7b888a7","status":"affected","versionType":"git"},{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"9669fa17287c3af2bbd4868d4c8fdd9e57f8332e","status":"affected","versionType":"git"},{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"67bb7521b6420d81dab7538c0686f18f7d6d09f4","status":"affected","versionType":"git"},{"version":"a0bc32b3cacf194dc479b342f006203fd1e1941a","lessThan":"4c1cdec319b9aadb65737c3eb1f5cb74bd6aa156","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["arch/x86/kernel/cpu/mce/amd.c"],"versions":[{"version":"5.10","status":"affected"},{"version":"0","lessThan":"5.10","status":"unaffected","versionType":"semver"},{"version":"5.10.180","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.111","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.28","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.2.15","lessThanOrEqual":"6.2.*","status":"unaffected","versionType":"semver"},{"version":"6.3.2","lessThanOrEqual":"6.3.*","status":"unaffected","versionType":"semver"},{"version":"6.4","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.10.180"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"5.15.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.1.28"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.2.15"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.3.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.10","versionEndExcluding":"6.4"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/a9b9ea0e63a0ec5e97bf1219ab6dcbd55e362f83"},{"url":"https://git.kernel.org/stable/c/11c58a0c1937c157dbdf82d5ab634d68c99f3098"},{"url":"https://git.kernel.org/stable/c/ba8ffb1251eb629c2ec35220e3896cf4f7b888a7"},{"url":"https://git.kernel.org/stable/c/9669fa17287c3af2bbd4868d4c8fdd9e57f8332e"},{"url":"https://git.kernel.org/stable/c/67bb7521b6420d81dab7538c0686f18f7d6d09f4"},{"url":"https://git.kernel.org/stable/c/4c1cdec319b9aadb65737c3eb1f5cb74bd6aa156"}],"title":"x86/MCE/AMD: Use an u64 for bank_map","x_generator":{"engine":"bippy-1.2.0"}}}}