arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP

{
  "id": "e22094b9f54bae12f24e30e0507edeeda92255528934e6bb5b7fb5b4f924e676",
  "url": "https://osv.dev/vulnerability/CVE-2025-38169",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "arm64/fpsimd: Avoid clobbering kernel FPSIMD state with SMSTOP",
    "summary": "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.",
    "evidence": "osv:CVE-2025-38169",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.34",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.15.3",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-38169",
      "aliases": [
        "CVE-2025-38169"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
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              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "fixed": "a305821f597ec943849d3e53924adb88c61ed682"
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                  "fixed": "01098d893fa8a6edb2b56e178b798e3e6b674f02"
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            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "6.8.12"
                },
                {
                  "fixed": "6.9"
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            },
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "6.9.3"
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                  "fixed": "6.10"
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              "events": [
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          "versions": [
            "v6.8.12",
            "v6.9.12",
            "v6.9.11",
            "v6.9.10",
            "v6.9.9",
            "v6.9.8",
            "v6.9.7",
            "v6.9.6",
            "v6.9.5",
            "v6.9.4",
            "v6.9.3"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38169.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.10.0"
                },
                {
                  "fixed": "6.12.34"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.15.3"
                }
              ]
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38169.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:31.218092353Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/01098d893fa8a6edb2b56e178b798e3e6b674f02",
        "https://git.kernel.org/stable/c/55d52af498daea75aa03ba9b7e444c8ae495ac20",
        "https://git.kernel.org/stable/c/a305821f597ec943849d3e53924adb88c61ed682",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38169.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-38169",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38169.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-38169",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497882,
  "published_at": "2025-07-03T08:36:08.393+00:00"
}