CVE-2026-64512 ACPI: CPPC: Suppress UBSAN warning caused by field misuse
A local attacker can trigger a kernel crash via an integer overflow in ACPI CPPC handling, affecting Linux kernel stability.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64512?
CVE-2026-64512 is a vulnerability in Linux, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official 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.
Which versions are affected by CVE-2026-64512?
How do I fix CVE-2026-64512?
Apply the vendor's patch.
Is CVE-2026-64512 being exploited?
There is no known exploitation of CVE-2026-64512 in the wild and no public exploit code.
Sources
Also known as AZL-93852, BELL-CVE-2026-64512, DEBIAN-CVE-2026-64512, GHSA-gqx5-8446-4x25, ROOT-OS-UBUNTU-2204-CVE-2026-64512, UBUNTU-CVE-2026-64512.