In the Linux kernel, the following vulnerability has been resolved:
ACPI: CPPC: Suppress UBSAN warning caused by field misuse
The definition of reg->access_width changes depending on the
reg->space_id type. Type ACPI_ADR_SPACE_PLATFORM_COMM uses
access_width to indicate the PCC region, which can result in a UBSAN
if the value is greater than 4.
For example:
UBSAN: shift-out-of-bounds in drivers/acpi/cppc_acpi.c:1090:9
shift exponent 32 is too large for 32-bit type 'int'
CPU: 61 UID: 0 PID: 1220 Comm: (udev-worker) Not tainted 7.0.10-201.fc44.aarch64 #1 PREEMPT(lazy)
Hardware name: To be filled by O.E.M.
Call trace:
...(trimming)
ubsan_epilogue+0x10/0x48
__ubsan_handle_shift_out_of_bounds+0xdc/0x1e0
cpc_write+0x4d0/0x670
cppc_set_perf+0x18c/0x490
cppc_cpufreq_cpu_init+0x1c8/0x380 [cppc_cpufreq]
... (trimming)
Lets fix this by validating the region type, as well as whether
access_width has a value. Then since we are returning bit_width
directly for ACPI_ADR_SPACE_PLATFORM_COMM, drop the code correcting
the size.
ACPI: CPPC: Suppress UBSAN warning caused by field misuse
The definition of reg->access_width changes depending on the
reg->space_id type. Type ACPI_ADR_SPACE_PLATFORM_COMM uses
access_width to indicate the PCC region, which can result in a UBSAN
if the value is greater than 4.
For example:
UBSAN: shift-out-of-bounds in drivers/acpi/cppc_acpi.c:1090:9
shift exponent 32 is too large for 32-bit type 'int'
CPU: 61 UID: 0 PID: 1220 Comm: (udev-worker) Not tainted 7.0.10-201.fc44.aarch64 #1 PREEMPT(lazy)
Hardware name: To be filled by O.E.M.
Call trace:
...(trimming)
ubsan_epilogue+0x10/0x48
__ubsan_handle_shift_out_of_bounds+0xdc/0x1e0
cpc_write+0x4d0/0x670
cppc_set_perf+0x18c/0x490
cppc_cpufreq_cpu_init+0x1c8/0x380 [cppc_cpufreq]
... (trimming)
Lets fix this by validating the region type, as well as whether
access_width has a value. Then since we are returning bit_width
directly for ACPI_ADR_SPACE_PLATFORM_COMM, drop the code correcting
the size.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
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| Linux | Linux | affected |
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Advisories
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Fixes
Solution
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Workaround
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References
History
Sat, 25 Jul 2026 09:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: ACPI: CPPC: Suppress UBSAN warning caused by field misuse The definition of reg->access_width changes depending on the reg->space_id type. Type ACPI_ADR_SPACE_PLATFORM_COMM uses access_width to indicate the PCC region, which can result in a UBSAN if the value is greater than 4. For example: UBSAN: shift-out-of-bounds in drivers/acpi/cppc_acpi.c:1090:9 shift exponent 32 is too large for 32-bit type 'int' CPU: 61 UID: 0 PID: 1220 Comm: (udev-worker) Not tainted 7.0.10-201.fc44.aarch64 #1 PREEMPT(lazy) Hardware name: To be filled by O.E.M. Call trace: ...(trimming) ubsan_epilogue+0x10/0x48 __ubsan_handle_shift_out_of_bounds+0xdc/0x1e0 cpc_write+0x4d0/0x670 cppc_set_perf+0x18c/0x490 cppc_cpufreq_cpu_init+0x1c8/0x380 [cppc_cpufreq] ... (trimming) Lets fix this by validating the region type, as well as whether access_width has a value. Then since we are returning bit_width directly for ACPI_ADR_SPACE_PLATFORM_COMM, drop the code correcting the size. | |
| Title | ACPI: CPPC: Suppress UBSAN warning caused by field misuse | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
|
Projects
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MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-07-25T08:52:04.423Z
Reserved: 2026-07-19T15:36:31.793Z
Link: CVE-2026-64512
Vulnrichment
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NVD
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Redhat
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OpenCVE Enrichment
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Weaknesses
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