x86/microcode/AMD: Fix out-of-bounds on systems with CPU-less NUMA nodes
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Configuration 1 [-]
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| Package | CPE | Advisory | Released Date |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | |||
| kernel-0:6.12.0-55.20.1.el10_0 | cpe:/o:redhat:enterprise_linux:10.0 | RHSA-2025:10371 | 2025-07-07T00:00:00Z |
No data available yet.
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-4178-1 | linux security update |
Debian DLA |
DLA-4193-1 | linux-6.1 security update |
Debian DSA |
DSA-5900-1 | linux security update |
EUVD |
EUVD-2025-9538 | In the Linux kernel, the following vulnerability has been resolved: x86/microcode/AMD: Fix out-of-bounds on systems with CPU-less NUMA nodes Currently, load_microcode_amd() iterates over all NUMA nodes, retrieves their CPU masks and unconditionally accesses per-CPU data for the first CPU of each mask. According to Documentation/admin-guide/mm/numaperf.rst: "Some memory may share the same node as a CPU, and others are provided as memory only nodes." Therefore, some node CPU masks may be empty and wouldn't have a "first CPU". On a machine with far memory (and therefore CPU-less NUMA nodes): - cpumask_of_node(nid) is 0 - cpumask_first(0) is CONFIG_NR_CPUS - cpu_data(CONFIG_NR_CPUS) accesses the cpu_info per-CPU array at an index that is 1 out of bounds This does not have any security implications since flashing microcode is a privileged operation but I believe this has reliability implications by potentially corrupting memory while flashing a microcode update. When booting with CONFIG_UBSAN_BOUNDS=y on an AMD machine that flashes a microcode update. I get the following splat: UBSAN: array-index-out-of-bounds in arch/x86/kernel/cpu/microcode/amd.c:X:Y index 512 is out of range for type 'unsigned long[512]' [...] Call Trace: dump_stack __ubsan_handle_out_of_bounds load_microcode_amd request_microcode_amd reload_store kernfs_fop_write_iter vfs_write ksys_write do_syscall_64 entry_SYSCALL_64_after_hwframe Change the loop to go over only NUMA nodes which have CPUs before determining whether the first CPU on the respective node needs microcode update. [ bp: Massage commit message, fix typo. ] |
Ubuntu USN |
USN-7585-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7585-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7585-3 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7585-4 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7585-5 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7585-6 | Linux kernel (BlueField) vulnerabilities |
Ubuntu USN |
USN-7585-7 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7591-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7591-2 | Linux kernel (FIPS) vulnerabilities |
Ubuntu USN |
USN-7591-3 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7591-4 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-7591-5 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-7591-6 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7592-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7593-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7597-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7597-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-7598-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7602-1 | Linux kernel (Xilinx ZynqMP) vulnerabilities |
Ubuntu USN |
USN-7605-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7605-2 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-7606-1 | Linux kernel (OEM) vulnerabilities |
Ubuntu USN |
USN-7628-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7640-1 | Linux kernel (IoT) vulnerabilities |
Ubuntu USN |
USN-7655-1 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-7764-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7764-2 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7765-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-7766-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-7767-1 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7767-2 | Linux kernel (Real-time) vulnerabilities |
Ubuntu USN |
USN-7779-1 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-7790-1 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-7800-1 | Linux kernel (Raspberry Pi Real-time) vulnerabilities |
Ubuntu USN |
USN-7801-1 | Linux kernel (HWE) vulnerabilities |
Ubuntu USN |
USN-7802-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-7801-2 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-7809-1 | Linux kernel (Azure, N-Series) vulnerabilities |
Ubuntu USN |
USN-7801-3 | Linux kernel (Oracle) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.225% probability within 30 days)
| Type | Values Removed | Values Added |
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| References |
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| Type | Values Removed | Values Added |
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| Metrics |
ssvc
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| Type | Values Removed | Values Added |
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| First Time appeared |
Redhat
Redhat enterprise Linux |
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| CPEs | cpe:/o:redhat:enterprise_linux:10.0 | |
| Vendors & Products |
Redhat
Redhat enterprise Linux |
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-787 |
| Type | Values Removed | Values Added |
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| First Time appeared |
Linux
Linux linux Kernel |
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| Weaknesses | CWE-129 | |
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc5:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:6.14:rc6:*:*:*:*:*:* |
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| Vendors & Products |
Linux
Linux linux Kernel |
|
| Metrics |
cvssV3_1
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cvssV3_1
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| Type | Values Removed | Values Added |
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| References |
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| Metrics |
threat_severity
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cvssV3_1
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| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: x86/microcode/AMD: Fix out-of-bounds on systems with CPU-less NUMA nodes Currently, load_microcode_amd() iterates over all NUMA nodes, retrieves their CPU masks and unconditionally accesses per-CPU data for the first CPU of each mask. According to Documentation/admin-guide/mm/numaperf.rst: "Some memory may share the same node as a CPU, and others are provided as memory only nodes." Therefore, some node CPU masks may be empty and wouldn't have a "first CPU". On a machine with far memory (and therefore CPU-less NUMA nodes): - cpumask_of_node(nid) is 0 - cpumask_first(0) is CONFIG_NR_CPUS - cpu_data(CONFIG_NR_CPUS) accesses the cpu_info per-CPU array at an index that is 1 out of bounds This does not have any security implications since flashing microcode is a privileged operation but I believe this has reliability implications by potentially corrupting memory while flashing a microcode update. When booting with CONFIG_UBSAN_BOUNDS=y on an AMD machine that flashes a microcode update. I get the following splat: UBSAN: array-index-out-of-bounds in arch/x86/kernel/cpu/microcode/amd.c:X:Y index 512 is out of range for type 'unsigned long[512]' [...] Call Trace: dump_stack __ubsan_handle_out_of_bounds load_microcode_amd request_microcode_amd reload_store kernfs_fop_write_iter vfs_write ksys_write do_syscall_64 entry_SYSCALL_64_after_hwframe Change the loop to go over only NUMA nodes which have CPUs before determining whether the first CPU on the respective node needs microcode update. [ bp: Massage commit message, fix typo. ] | |
| Title | x86/microcode/AMD: Fix out-of-bounds on systems with CPU-less NUMA nodes | |
| References |
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