CVE-2025-38169

arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP

Description

In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP On system with SME, a thread's kernel FPSIMD state may be erroneously clobbered during a context switch immediately after that state is restored. Systems without SME are unaffected. If the CPU happens to be in streaming SVE mode before a context switch to a thread with kernel FPSIMD state, fpsimd_thread_switch() will restore the kernel FPSIMD state using fpsimd_load_kernel_state() while the CPU is still in streaming SVE mode. When fpsimd_thread_switch() subsequently calls fpsimd_flush_cpu_state(), this will execute an SMSTOP, causing an exit from streaming SVE mode. The exit from streaming SVE mode will cause the hardware to reset a number of FPSIMD/SVE/SME registers, clobbering the FPSIMD state. Fix this by calling fpsimd_flush_cpu_state() before restoring the kernel FPSIMD state.

N/A

CVSS

Severity:

EPSS 0.02%

Affected: Linux Linux

References

Link	Tags
https://git.kernel.org/stable/c/55d52af498daea75aa03ba9b7e444c8ae495ac20
https://git.kernel.org/stable/c/a305821f597ec943849d3e53924adb88c61ed682
https://git.kernel.org/stable/c/01098d893fa8a6edb2b56e178b798e3e6b674f02

Frequently Asked Questions

What is the severity of CVE-2025-38169?: CVE-2025-38169 has not yet been assigned a CVSS score.
How to fix CVE-2025-38169?: To fix CVE-2025-38169, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2025-38169 being actively exploited in the wild?: As for now, there are no information to confirm that CVE-2025-38169 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2025-38169?: CVE-2025-38169 affects Linux Linux, Linux Linux.

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