ACPI: CPPC: Suppress UBSAN warning caused by field misuse

Summary

CVECVE-2026-64512
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-25 10:17:37 UTC
Updated2026-07-25 10:17:37 UTC
DescriptionIn 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.

Risk And Classification

EPSS: 0.001730000 probability, percentile 0.069960000 (date 2026-07-29)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 4949affd5288b867cdf115f5b08d6166b2027f87 b54c4632946ae42f2b39ed38abd909bbf78cbcc2 git Not specified
CNA Linux Linux affected 01fc53be672acae37e611c80cc0b4f3939584de3 e904596ba6dd108534ffa15e3e46b2fe245145e2 git Not specified
CNA Linux Linux affected 1b890ae474d19800a6be1696df7fb4d9a41676e4 2fb80e962029000959f651665baa4838cc92eb99 git Not specified
CNA Linux Linux affected 2f4a4d63a193be6fd530d180bb13c3592052904c 37f28bf8f14672dfa395994e41fd778a63f0bf5c git Not specified
CNA Linux Linux affected 2f4a4d63a193be6fd530d180bb13c3592052904c f29dc6132d4968e39d8fa575d1a12e2c718ce57b git Not specified
CNA Linux Linux affected 2f4a4d63a193be6fd530d180bb13c3592052904c dc066bd13c860bb27d6ace511210e18b8064c1d9 git Not specified
CNA Linux Linux affected 2f4a4d63a193be6fd530d180bb13c3592052904c 1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1 git Not specified
CNA Linux Linux affected 6cb6b12b78dcd8867a3fdbb1b6d0ed1df2b208d1 git Not specified
CNA Linux Linux affected 5.15.154 5.15.155 semver Not specified
CNA Linux Linux affected 6.1.90 6.1.178 semver Not specified
CNA Linux Linux affected 6.6.30 6.6.145 semver Not specified
CNA Linux Linux affected 6.8.9 6.9 semver Not specified
CNA Linux Linux affected 6.9 Not specified
CNA Linux Linux unaffected 6.9 semver Not specified
CNA Linux Linux unaffected 5.15.155 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.178 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.96 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.39 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.4 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2-rc1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/2fb80e962029000959f651665baa4838cc92eb99 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b54c4632946ae42f2b39ed38abd909bbf78cbcc2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e904596ba6dd108534ffa15e3e46b2fe245145e2 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/dc066bd13c860bb27d6ace511210e18b8064c1d9 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/37f28bf8f14672dfa395994e41fd778a63f0bf5c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f29dc6132d4968e39d8fa575d1a12e2c718ce57b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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