arm64/fpsimd: ptrace: Fix SVE writes on !SME systems

{
  "id": "8f10d649a7f9411700ae9d8455849b1060160ec4836dcc81cfeac1c727f9906f",
  "url": "https://osv.dev/vulnerability/CVE-2026-23114",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "arm64/fpsimd: ptrace: Fix SVE writes on !SME systems",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: arm64/fpsimd: ptrace: Fix SVE writes on !SME systems When SVE is supported but SME is not supported, a ptrace write to the NT_ARM_SVE regset can place the tracee into an invalid state where (non-streaming) SVE register data is stored in FP_STATE_SVE format but TIF_SVE is clear. This can result in a later warning from fpsimd_restore_current_state(), e.g. WARNING: CPU: 0 PID: 7214 at arch/arm64/kernel/fpsimd.c:383 fpsimd_restore_current_state+0x50c/0x748 When this happens, fpsimd_restore_current_state() will set TIF_SVE, placing the task into the correct state. This occurs before any other check of TIF_SVE can possibly occur, as other checks of TIF_SVE only happen while the FPSIMD/SVE/SME state is live. Thus, aside from the warning, there is no functional issue. This bug was introduced during rework to error handling in commit: 9f8bf718f2923 (\"arm64/fpsimd: ptrace: Gracefully handle errors\") ... where the setting of TIF_SVE was moved into a block which is only executed when system_supports_sme() is true. Fix this by removing the system_supports_sme() check. This ensures that TIF_SVE is set for (SVE-formatted) writes to NT_ARM_SVE, at the cost of unconditionally manipulating the tracee's saved svcr value. The manipulation of svcr is benign and inexpensive, and we already do similar elsewhere (e.g. during signal handling), so I don't think it's worth guarding this with system_supports_sme() checks. Aside from the",
    "evidence": "osv:CVE-2026-23114",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-23114",
      "aliases": [
        "CVE-2026-23114"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "9f8bf718f29230e38a048d08fc3063e316cd60c1"
                },
                {
                  "fixed": "4f39984176e7edcaba3432b6c649c6fe93bf2f80"
                },
                {
                  "fixed": "128a7494a9f15aad60cc6b7e3546bf481ac54a13"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23114.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.16.0"
                },
                {
                  "fixed": "6.18.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23114.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:32.509224679Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/128a7494a9f15aad60cc6b7e3546bf481ac54a13",
        "https://git.kernel.org/stable/c/4f39984176e7edcaba3432b6c649c6fe93bf2f80",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23114.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-23114",
        "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/2026/23xxx/CVE-2026-23114.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-23114",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 499368,
  "published_at": "2026-02-14T15:09:47.048+00:00"
}