UBUNTU-CVE-2025-38170: Low severity ubuntu/linux-hwe-edge vulnerability

Q: Which deployments are relevant to this issue?

The issue is in the arm64 FPSIMD/SVE/SME trap-handling path. The affected Ubuntu package set listed includes linux-azure-fde, linux-riscv, linux-realtime, linux-hwe-edge, linux-azure, linux-gcp, linux-gke, and linux-gkeop.

Q: What conditions are needed to trigger the race?

A local attacker needs low privileges and must cause SME trap handling while preemption races with manipulation of saved FPSIMD/SVE/SME state. The described race involves a task being preempted and migrated between CPUs during handling.

Q: How can administrators recognize that the problematic state has occurred?

The kernel may emit warnings from do_sme_acc() indicating that SME traps occurred unexpectedly while TIF_SME was already set. The warning condition described is test_and_set_thread_flag(TIF_SME) returning true.

Q: What is the expected security impact?

The provided severity vector indicates low severity with local attack access, low privileges required, and partial availability impact. It indicates no confidentiality or integrity impact and no impact on subsequent systems.

Published Jul 3, 2025

Updated

In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: Discard stale CPU state when handling SME traps The logic for handling SME traps manipulates saved FPSIMD/SVE/SME state incorrectly, and a race with preemption can result in a task having TIFSME set and TIFFOREIGNFPSTATE clear even though the live CPU state is stale (e.g. with SME traps enabled). This can result in warnings from dosmeacc() where SME traps are not expected while TIFSME is set: | / With TIFSME userspace shouldn't generate any traps / | if (testandsetthreadflag(TIFSME)) | WARNON(1); This is very similar to the SVE issue we fixed in commit: 751ecf6afd6568ad ("arm64/sve: Discard stale CPU state when handling SVE traps") The race can occur when the SME trap handler is preempted before and after manipulating the saved FPSIMD/SVE/SME state, starting and ending on the same CPU, e.g. | void dosmeacc(unsigned long esr, struct ptregs regs) | { | // Trap on CPU 0 with TIFSME clear, SME traps enabled | // task->fpsimdcpu is 0. | // percpuptr(&fpsimdlaststate, 0) is task. | | ... | | // Preempted; migrated from CPU 0 to CPU 1. | // TIFFOREIGNFPSTATE is set. | | getcpufpsimdcontext(); | | / With TIFSME userspace shouldn't generate any traps / | if (testandsetthreadflag(TIFSME)) | WARNON(1); | | if (!testthreadflag(TIFFOREIGNFPSTATE)) { | unsigned long vqminusone = | svevqfromvl(taskgetsmevl(current)) - 1; | smesetvq(vqminusone); | | fpsimdbindtasktocpu(); | } | | putcpufpsimdcontext(); | | // Preempted; migrated from CPU 1 to CPU 0. | // task->fpsimdcpu is still 0 | // If percpuptr(&fpsimdlaststate, 0) is still task then: | // - Stale HW state is reused (with SME traps enabled) | // - TIFFOREIGNFPSTATE is cleared | // - A return to userspace skips HW state restore | } Fix the case where the state is not live and TIFFOREIGNFPSTATE is set by calling fpsimdflushtaskstate() to detach from the saved CPU state. This ensures that a subsequent context switch will not reuse the stale CPU state, and will instead set TIFFOREIGNFPSTATE, forcing the new state to be reloaded from memory prior to a return to userspace. Note: this was originallly posted as [1]. [ Rutland: rewrite commit message ]

Affected Software

131 affected componentsFixes available

ubuntu/linux-hwe-edge*

ubuntu/linux-aws-5.0*

ubuntu/linux-aws-5.3*

ubuntu/linux-azure*

ubuntu/linux-azure-5.3*

ubuntu/linux-azure-edge*

ubuntu/linux-gcp*

ubuntu/linux-gcp-5.3*

ubuntu/linux-gke-4.15*

ubuntu/linux-gke-5.4*

ubuntu/linux-gkeop-5.4*

ubuntu/linux-hwe*

ubuntu/linux-hwe-edge*

ubuntu/linux-oem*

ubuntu/linux-oracle-5.0*

ubuntu/linux-oracle-5.3*

ubuntu/linux-aws-5.11*

ubuntu/linux-aws-5.13*

ubuntu/linux-aws-5.8*

ubuntu/linux-azure-5.11*

ubuntu/linux-azure-5.13*

ubuntu/linux-azure-5.8*

ubuntu/linux-azure-fde*

ubuntu/linux-gcp-5.11*

ubuntu/linux-gcp-5.13*

ubuntu/linux-gcp-5.8*

ubuntu/linux-gke*

ubuntu/linux-gke-5.15*

ubuntu/linux-gkeop*

ubuntu/linux-gkeop-5.15*

ubuntu/linux-hwe-5.11*

ubuntu/linux-hwe-5.13*

ubuntu/linux-hwe-5.8*

ubuntu/linux-intel-5.13*

ubuntu/linux-oem-5.10*

ubuntu/linux-oem-5.13*

ubuntu/linux-oem-5.6*

ubuntu/linux-oracle-5.11*

ubuntu/linux-oracle-5.13*

ubuntu/linux-oracle-5.8*

ubuntu/linux-raspi2*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.11*

ubuntu/linux-riscv-5.8*

ubuntu/linux-allwinner-5.19*

ubuntu/linux-aws-5.19*

ubuntu/linux-aws-6.2*

ubuntu/linux-aws-6.5*

ubuntu/linux-aws-6.8<6.8.0-1046.49~22.04.1

6.8.0-1046.49~22.04.1

ubuntu/linux-azure-5.19*

ubuntu/linux-azure-6.2*

ubuntu/linux-azure-6.5*

ubuntu/linux-azure-6.8<6.8.0-1051.57~22.04.1

6.8.0-1051.57~22.04.1

ubuntu/linux-azure-fde-5.19*

ubuntu/linux-azure-fde-6.2*

ubuntu/linux-azure-fde-6.8<6.8.0-1046.53~22.04.1

6.8.0-1046.53~22.04.1

ubuntu/linux-gcp-5.19*

ubuntu/linux-gcp-6.2*

ubuntu/linux-gcp-6.5*

ubuntu/linux-gcp-6.8<6.8.0-1047.50~22.04.2

6.8.0-1047.50~22.04.2

ubuntu/linux-hwe-5.19*

ubuntu/linux-hwe-6.2*

ubuntu/linux-hwe-6.5*

ubuntu/linux-hwe-6.8<6.8.0-100.100~22.04.1

6.8.0-100.100~22.04.1

ubuntu/linux-ibm-6.8<6.8.0-1044.44~22.04.1

6.8.0-1044.44~22.04.1

ubuntu/linux-intel-iot-realtime*

ubuntu/linux-lowlatency-hwe-5.19*

ubuntu/linux-lowlatency-hwe-6.2*

ubuntu/linux-lowlatency-hwe-6.5*

ubuntu/linux-lowlatency-hwe-6.8<6.8.0-100.100.1~22.04.1

6.8.0-100.100.1~22.04.1

ubuntu/linux-nvidia-6.2*

ubuntu/linux-nvidia-6.5*

ubuntu/linux-nvidia-6.8<6.8.0-1046.49~22.04.1

6.8.0-1046.49~22.04.1

ubuntu/linux-oem-5.17*

ubuntu/linux-oem-6.0*

ubuntu/linux-oem-6.1*

ubuntu/linux-oem-6.5*

ubuntu/linux-oracle-6.5*

ubuntu/linux-oracle-6.8<6.8.0-1043.44~22.04.1

6.8.0-1043.44~22.04.1

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-5.19*

ubuntu/linux-riscv-6.5*

ubuntu/linux-riscv-6.8<6.8.0-100.100~22.04.1

6.8.0-100.100~22.04.1

ubuntu/linux-starfive-5.19*

ubuntu/linux-starfive-6.2*

ubuntu/linux-starfive-6.5*

ubuntu/linux-realtime-6.8<6.8.1-1041.42~22.04.1

6.8.1-1041.42~22.04.1

ubuntu/linux<6.8.0-100.100

6.8.0-100.100

ubuntu/linux-aws<6.8.0-1046.49

6.8.0-1046.49

ubuntu/linux-aws-6.14<6.14.0-1013.13~24.04.1

6.14.0-1013.13~24.04.1

ubuntu/linux-azure<6.8.0-1046.52

6.8.0-1046.52

ubuntu/linux-azure-6.11*

ubuntu/linux-azure-fde<6.8.0-1046.53

6.8.0-1046.53

ubuntu/linux-azure-nvidia<6.8.0-1039.42

6.8.0-1039.42

ubuntu/linux-azure-nvidia-6.14<6.14.0-1007.7

6.14.0-1007.7

ubuntu/linux-gcp<6.8.0-1047.50

6.8.0-1047.50

ubuntu/linux-gcp-6.11*

ubuntu/linux-gcp-6.14<6.14.0-1016.17~24.04.1

6.14.0-1016.17~24.04.1

ubuntu/linux-gke<6.8.0-1043.48

6.8.0-1043.48

ubuntu/linux-gkeop<6.8.0-1030.33

6.8.0-1030.33

ubuntu/linux-hwe-6.11*

ubuntu/linux-ibm<6.8.0-1044.44

6.8.0-1044.44

ubuntu/linux-intel*

ubuntu/linux-lowlatency<6.8.0-100.100.1

6.8.0-100.100.1

ubuntu/linux-lowlatency-hwe-6.11*

ubuntu/linux-nvidia<6.8.0-1046.49

6.8.0-1046.49

ubuntu/linux-nvidia-6.11*

ubuntu/linux-nvidia-lowlatency<6.8.0-1046.49.1

6.8.0-1046.49.1

ubuntu/linux-nvidia-tegra<6.8.0-1020.20

6.8.0-1020.20

ubuntu/linux-oem-6.11*

ubuntu/linux-oem-6.14<6.14.0-1012.12

6.14.0-1012.12

ubuntu/linux-oem-6.8*

ubuntu/linux-oracle<6.8.0-1043.44

6.8.0-1043.44

ubuntu/linux-oracle-6.14<6.14.0-1013.13~24.04.1

6.14.0-1013.13~24.04.1

ubuntu/linux-raspi<6.8.0-1047.51

6.8.0-1047.51

ubuntu/linux-raspi-realtime*

ubuntu/linux-realtime*

ubuntu/linux-riscv*

ubuntu/linux-riscv-6.14<6.14.0-32.32.1~24.04.1

6.14.0-32.32.1~24.04.1

ubuntu/linux-xilinx<6.8.0-1023.24

6.8.0-1023.24

ubuntu/linux-bluefield<6.8.0-1016.20

6.8.0-1016.20

ubuntu/linux-raspi-realtime<6.8.0-2037.38

6.8.0-2037.38

ubuntu/linux-realtime<6.8.1-1041.42

6.8.1-1041.42

ubuntu/linux-realtime-6.14<6.14.0-1012.12~24.04.1

6.14.0-1012.12~24.04.1

ubuntu/linux-aws-fips<6.8.0-1046.49+fips1

6.8.0-1046.49+fips1

ubuntu/linux-azure-fips<6.8.0-1046.52+fips1

6.8.0-1046.52+fips1

ubuntu/linux-fips<6.8.0-100.100+fips1

6.8.0-100.100+fips1

ubuntu/linux-gcp-fips<6.8.0-1047.50+fips1

6.8.0-1047.50+fips1

ubuntu/linux-azure-fde*

ubuntu/linux-vmware*

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade ubuntu/linux-aws-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1051.57~22.04.1
Upgrade
Upgrade ubuntu/linux-azure-fde-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.53~22.04.1
Upgrade
Upgrade ubuntu/linux-gcp-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1047.50~22.04.2
Upgrade
Upgrade ubuntu/linux-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100~22.04.1
Upgrade
Upgrade ubuntu/linux-ibm-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1044.44~22.04.1
Upgrade
Upgrade ubuntu/linux-lowlatency-hwe-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100.1~22.04.1
Upgrade
Upgrade ubuntu/linux-nvidia-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49~22.04.1
Upgrade
Upgrade ubuntu/linux-oracle-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-1043.44~22.04.1
Upgrade
Upgrade ubuntu/linux-riscv-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100~22.04.1
Upgrade
Upgrade ubuntu/linux-realtime-6.8 to a version that resolves this vulnerability.
Fixed in 6.8.1-1041.42~22.04.1
Upgrade
Upgrade ubuntu/linux to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100
Upgrade
Upgrade ubuntu/linux-aws to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49
Upgrade
Upgrade ubuntu/linux-aws-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1013.13~24.04.1
Upgrade
Upgrade ubuntu/linux-azure to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.52
Upgrade
Upgrade ubuntu/linux-azure-fde to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.53
Upgrade
Upgrade ubuntu/linux-azure-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1039.42
Upgrade
Upgrade ubuntu/linux-azure-nvidia-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1007.7
Upgrade
Upgrade ubuntu/linux-gcp to a version that resolves this vulnerability.
Fixed in 6.8.0-1047.50
Upgrade
Upgrade ubuntu/linux-gcp-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1016.17~24.04.1
Upgrade
Upgrade ubuntu/linux-gke to a version that resolves this vulnerability.
Fixed in 6.8.0-1043.48
Upgrade
Upgrade ubuntu/linux-gkeop to a version that resolves this vulnerability.
Fixed in 6.8.0-1030.33
Upgrade
Upgrade ubuntu/linux-ibm to a version that resolves this vulnerability.
Fixed in 6.8.0-1044.44
Upgrade
Upgrade ubuntu/linux-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100.1
Upgrade
Upgrade ubuntu/linux-nvidia to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49
Upgrade
Upgrade ubuntu/linux-nvidia-lowlatency to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49.1
Upgrade
Upgrade ubuntu/linux-nvidia-tegra to a version that resolves this vulnerability.
Fixed in 6.8.0-1020.20
Upgrade
Upgrade ubuntu/linux-oem-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1012.12
Upgrade
Upgrade ubuntu/linux-oracle to a version that resolves this vulnerability.
Fixed in 6.8.0-1043.44
Upgrade
Upgrade ubuntu/linux-oracle-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1013.13~24.04.1
Upgrade
Upgrade ubuntu/linux-raspi to a version that resolves this vulnerability.
Fixed in 6.8.0-1047.51
Upgrade
Upgrade ubuntu/linux-riscv-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-32.32.1~24.04.1
Upgrade
Upgrade ubuntu/linux-xilinx to a version that resolves this vulnerability.
Fixed in 6.8.0-1023.24
Upgrade
Upgrade ubuntu/linux-bluefield to a version that resolves this vulnerability.
Fixed in 6.8.0-1016.20
Upgrade
Upgrade ubuntu/linux-raspi-realtime to a version that resolves this vulnerability.
Fixed in 6.8.0-2037.38
Upgrade
Upgrade ubuntu/linux-realtime to a version that resolves this vulnerability.
Fixed in 6.8.1-1041.42
Upgrade
Upgrade ubuntu/linux-realtime-6.14 to a version that resolves this vulnerability.
Fixed in 6.14.0-1012.12~24.04.1
Upgrade
Upgrade ubuntu/linux-aws-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.49+fips1
Upgrade
Upgrade ubuntu/linux-azure-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1046.52+fips1
Upgrade
Upgrade ubuntu/linux-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-100.100+fips1
Upgrade
Upgrade ubuntu/linux-gcp-fips to a version that resolves this vulnerability.
Fixed in 6.8.0-1047.50+fips1
Compensating control
In the arm64 FPSIMD/SME trap handling path, when the state is not live and TIF_FOREIGN_FPSTATE is set, call fpsimd_flush_task_state() to detach the task from the saved CPU state so a subsequent context switch reloads state from memory.

Event History

Jul 3, 2025

CVE Published

via OSV·09:15 AM

Data Sourced

via OSV·09:15 AM

DescriptionSeverityAffected Software

Frequently Asked Questions

Which deployments are relevant to this issue?

The issue is in the arm64 FPSIMD/SVE/SME trap-handling path. The affected Ubuntu package set listed includes linux-azure-fde, linux-riscv, linux-realtime, linux-hwe-edge, linux-azure, linux-gcp, linux-gke, and linux-gkeop.

What conditions are needed to trigger the race?

A local attacker needs low privileges and must cause SME trap handling while preemption races with manipulation of saved FPSIMD/SVE/SME state. The described race involves a task being preempted and migrated between CPUs during handling.

How can administrators recognize that the problematic state has occurred?

The kernel may emit warnings from do_sme_acc() indicating that SME traps occurred unexpectedly while TIF_SME was already set. The warning condition described is test_and_set_thread_flag(TIF_SME) returning true.

What is the expected security impact?

The provided severity vector indicates low severity with local attack access, low privileges required, and partial availability impact. It indicates no confidentiality or integrity impact and no impact on subsequent systems.

UBUNTU-CVE-2025-38170: Low severity ubuntu/linux-hwe-edge vulnerability

Affected Software

Remediation

Event History

Frequently Asked Questions

Which deployments are relevant to this issue?

What conditions are needed to trigger the race?

How can administrators recognize that the problematic state has occurred?

What is the expected security impact?

Company

Resources

Contact

Frequently Asked Questions

Which deployments are relevant to this issue?

What conditions are needed to trigger the race?

How can administrators recognize that the problematic state has occurred?

What is the expected security impact?