Kernel FPSIMD State Clobbering Vulnerability in Linux Package
Summary
DEBIAN-CVE-2025-38169: 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... Affects linux versions < 6.12.35-1. Fixed in 6.12.35-1. How to fix ↓
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Background
The Linux package is a core component of the Debian operating system, providing essential functionalities for managing hardware and system resources. It includes the Linux kernel, which is responsible for communication between software and hardware. This vulnerability affects the kernel's FPSIMD state management, particularly in systems with Scalable Matrix Extensions (SME), potentially leading to data corruption during context switches.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified where the kernel FPSIMD state may be erroneously clobbered during a context switch on systems with SME. This occurs when the CPU is in streaming SVE mode before switching to a thread with kernel FPSIMD state. The function fpsimd_thread_switch() restores the FPSIMD state while the CPU is still in streaming SVE mode, leading to a reset of FPSIMD/SVE/SME registers and corruption of the FPSIMD state. Systems without SME are unaffected by this issue.
How To Fix
Minimum fixed version
6.12.35-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, no specific workaround has been provided for this vulnerability. It is recommended to apply the patch as soon as it is available.
Conclusion
The vulnerability in the Linux kernel regarding FPSIMD state clobbering poses a significant risk to systems utilizing SME. It is essential to update to the patched version to ensure system integrity and performance. Regular monitoring for vulnerabilities using tools like Vulert can help maintain security in open-source software.
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FAQ
The vulnerability can lead to corruption of the kernel FPSIMD state, potentially affecting system stability and performance on systems with SME.
No, systems that do not utilize Scalable Matrix Extensions (SME) are unaffected by this vulnerability.
You can use the Vulert platform to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected without requiring any signup.
While no specific workaround is available, it is crucial to prioritize updating the package to mitigate the risk associated with this vulnerability.
This vulnerability was published on July 3, 2025.
References
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