CVE-2025-38169: Linux kernel · arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP
Source GCVE Database
Not known to be exploited · CVSS 5.5 Medium.
Data as of 13 Nov 2026, 18:29 UTC
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 3 Jul 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
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.
References
- nvd.nist.gov/vuln/detail/CVE-2025-38169 (opens in a new tab)
- git.kernel.org/stable/c/01098d893fa8a6edb2b56e178b798e3e6b674f02 (opens in a new tab)
- git.kernel.org/stable/c/55d52af498daea75aa03ba9b7e444c8ae495ac20 (opens in a new tab)
- git.kernel.org/stable/c/a305821f597ec943849d3e53924adb88c61ed682 (opens in a new tab)