ACPI: CPPC: Suppress UBSAN warning caused by field misuse
Key facts
- Attack vector
- —
- Privileges required
- —
- User interaction
- —
- Attack complexity
- —
- Impact type
- —
- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 2 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.15.154 to before 5.15.155; 6.1.90 to before 6.1.178; 6.6.30 to before 6.6.145; 6.8.9 to before 6.9 | 5.15.155, 6.1.178, 6.6.145, 6.9 | Patch available | CNA |
| Linux | Linux | 6.9 and later | 5.15.155, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 | Patch available | CNA |
- Linux VendorLinux Affected 5.15.154 to before 5.15.155; 6.1.90 to before 6.1.178; 6.6.30 to before 6.6.145; 6.8.9 to before 6.9 Fixed in 5.15.155, 6.1.178, 6.6.145, 6.9 Patch available CNA
- Linux VendorLinux Affected 6.9 and later Fixed in 5.15.155, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2 Patch available CNA
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.15.155, 6.1.178, 6.6.145, 6.9
- Fix · CNA Linux (Linux) Fixed in 5.15.155, 6.1.178, 6.6.145, 6.12.96, 6.18.39, 7.1.4, 7.2
Vendor assessments
Red Hat
Red Hat rating: Low. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-64512
- 2026-10-03 Alias added: GHSA-gqx5-8446-4x25
- 2026-10-29 Affected versions changed · Red Hat
- 2026-11-06 CISA SSVC decision points changed
References
Other 7
- https://git.kernel.org/stable/c/b54c4632946ae42f2b39ed38abd909bbf78cbcc2
- https://git.kernel.org/stable/c/e904596ba6dd108534ffa15e3e46b2fe245145e2
- https://git.kernel.org/stable/c/2fb80e962029000959f651665baa4838cc92eb99
- https://git.kernel.org/stable/c/37f28bf8f14672dfa395994e41fd778a63f0bf5c
- https://git.kernel.org/stable/c/f29dc6132d4968e39d8fa575d1a12e2c718ce57b
- https://git.kernel.org/stable/c/dc066bd13c860bb27d6ace511210e18b8064c1d9
- https://git.kernel.org/stable/c/1b1acf2dada0cc3931bb2cb9ff8832edfbee46a1
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Sources
- CVE-2026-64512 · CVE Program
- CVE-2026-64512 · NVD
- FIRST EPSS
- GHSA-gqx5-8446-4x25 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-64512 · Red Hat security data · CC BY 4.0
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