{"id":"CVE-2026-64512","title":"ACPI: CPPC: Suppress UBSAN warning caused by field misuse","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nACPI: CPPC: Suppress UBSAN warning caused by field misuse\n\nThe definition of reg->access_width changes depending on the\nreg->space_id type.  Type ACPI_ADR_SPACE_PLATFOR…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 4949affd5288b867cdf115f5b08d6166b2027f87 < b54c4632946ae42f2b39ed38abd909bbf78cbcc2","Linux >= 01fc53be672acae37e611c80cc0b4f3939584de3 < e904596ba6dd108534ffa15e3e46b2fe245145e2","Linux >= 1b890ae474d19800a6be1696df7fb4d9a41676e4 < 2fb80e962029000959f651665baa4838cc92eb99","Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < 37f28bf8f14672dfa395994e41fd778a63f0bf5c","Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < f29dc6132d4968e39d8fa575d1a12e2c718ce57b","Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < dc066bd13c860bb27d6ace511210e18b8064c1d9","Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < 1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1","Linux 6cb6b12b78dcd8867a3fdbb1b6d0ed1df2b208d1","Linux >= 5.15.154 < 5.15.155","Linux >= 6.1.90 < 6.1.178","Linux >= 6.6.30 < 6.6.145","Linux >= 6.8.9 < 6.9","Linux 6.9"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-06T16:40:51.386689Z"},"published":"2026-07-25","updated":"2026-11-06","sourceUpdated":"2026-11-06T16:44:56.109Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-64512","references":[{"url":"https://git.kernel.org/stable/c/b54c4632946ae42f2b39ed38abd909bbf78cbcc2"},{"url":"https://git.kernel.org/stable/c/e904596ba6dd108534ffa15e3e46b2fe245145e2"},{"url":"https://git.kernel.org/stable/c/2fb80e962029000959f651665baa4838cc92eb99"},{"url":"https://git.kernel.org/stable/c/37f28bf8f14672dfa395994e41fd778a63f0bf5c"},{"url":"https://git.kernel.org/stable/c/f29dc6132d4968e39d8fa575d1a12e2c718ce57b"},{"url":"https://git.kernel.org/stable/c/dc066bd13c860bb27d6ace511210e18b8064c1d9"},{"url":"https://git.kernel.org/stable/c/1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1"}],"tags":["cve.org"],"epss":0.00173,"epssPercentile":0.06788,"ingestedAt":"2026-11-06T16:57:43.157Z","slug":"CVE-2026-64512","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nACPI: CPPC: Suppress UBSAN warning caused by field misuse\n\nThe definition of reg->access_width changes depending on the\nreg->space_id type.  Type ACPI_ADR_SPACE_PLATFORM_COMM uses\naccess_width to indicate the PCC region, which can result in a UBSAN\nif the value is greater than 4.\n\nFor example:\n\n UBSAN: shift-out-of-bounds in drivers/acpi/cppc_acpi.c:1090:9\n shift exponent 32 is too large for 32-bit type 'int'\n CPU: 61 UID: 0 PID: 1220 Comm: (udev-worker) Not tainted 7.0.10-201.fc44.aarch64 #1 PREEMPT(lazy)\n Hardware name: To be filled by O.E.M.\n Call trace:\n  ...(trimming)\n  ubsan_epilogue+0x10/0x48\n  __ubsan_handle_shift_out_of_bounds+0xdc/0x1e0\n  cpc_write+0x4d0/0x670\n  cppc_set_perf+0x18c/0x490\n  cppc_cpufreq_cpu_init+0x1c8/0x380 [cppc_cpufreq]\n  ... (trimming)\n\nLets fix this by validating the region type, as well as whether\naccess_width has a value. Then since we are returning bit_width\ndirectly for ACPI_ADR_SPACE_PLATFORM_COMM, drop the code correcting\nthe size.\n\n## Affected\n\n- `Linux >= 4949affd5288b867cdf115f5b08d6166b2027f87 < b54c4632946ae42f2b39ed38abd909bbf78cbcc2`\n- `Linux >= 01fc53be672acae37e611c80cc0b4f3939584de3 < e904596ba6dd108534ffa15e3e46b2fe245145e2`\n- `Linux >= 1b890ae474d19800a6be1696df7fb4d9a41676e4 < 2fb80e962029000959f651665baa4838cc92eb99`\n- `Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < 37f28bf8f14672dfa395994e41fd778a63f0bf5c`\n- `Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < f29dc6132d4968e39d8fa575d1a12e2c718ce57b`\n- `Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < dc066bd13c860bb27d6ace511210e18b8064c1d9`\n- `Linux >= 2f4a4d63a193be6fd530d180bb13c3592052904c < 1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1`\n- `Linux 6cb6b12b78dcd8867a3fdbb1b6d0ed1df2b208d1`\n- `Linux >= 5.15.154 < 5.15.155`\n- `Linux >= 6.1.90 < 6.1.178`\n- `Linux >= 6.6.30 < 6.6.145`\n- `Linux >= 6.8.9 < 6.9`\n- `Linux 6.9`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}