perf/x86/amd/brs: Fix kernel address leakage

{
  "id": "edf78e4f8fce9f60b319d13e26dd68fd346868883df1228d00238d150be7042a",
  "url": "https://osv.dev/vulnerability/CVE-2026-72237",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "perf/x86/amd/brs: Fix kernel address leakage",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: perf/x86/amd/brs: Fix kernel address leakage A user-only branch stack can contain branches that originate from the kernel. As a result, kernel addresses are exposed to user space even when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors supporting X86_FEATURE_BRS (Zen 3 only), perf can still report entries such as SYSRET/interrupt returns for which the branch-from addresses are in the kernel. E.g. $ perf record -j any,u -c 4000 -e branch-brs -o - -- \\ perf bench syscall basic --loop 1000 | \\ perf script -i - -F brstack|tr ' ' '\\n'| \\ grep -E '0x[89a-f][0-9a-f]{15}' ... 0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//- 0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//- 0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//- ... BRS provides no hardware branch filtering, so privilege level filtering is performed entirely in software. However, amd_brs_match_plm() only validates the branch-to address against the requested privilege levels. For branches from the kernel to user space, the branch-from address is left unchecked and is leaked. Extend the software filter to also validate the branch-from address, so that any branch record whose branch-from address is in the kernel is dropped when PERF_SAMPLE_BRANCH_USER is requested.",
    "evidence": "osv:CVE-2026-72237",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.183",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.145",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.97",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.40",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.5",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-72237",
      "aliases": [
        "CVE-2026-72237"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
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                  "fixed": "4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1"
                },
                {
                  "fixed": "ac44b4a3d6137489f8fa2e794b12e849c6b22eaa"
                },
                {
                  "fixed": "90843d00dbc61220b66408ea0d8775cae9e51f70"
                },
                {
                  "fixed": "046f6244da9b68e463a849b21446b9424e531491"
                },
                {
                  "fixed": "2e706be56f418718bb3ae66c0aa94f9b61150e6d"
                },
                {
                  "fixed": "47915e855fb38b42133e31ba917d99565f862154"
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              ]
            }
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72237.json"
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        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                  "introduced": "5.19.0"
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                  "fixed": "6.1.183"
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                  "introduced": "6.2.0"
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            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "6.7.0"
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                {
                  "fixed": "6.12.97"
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              "type": "ECOSYSTEM",
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                  "introduced": "6.19.0"
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          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72237.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.170852617Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/046f6244da9b68e463a849b21446b9424e531491",
        "https://git.kernel.org/stable/c/2e706be56f418718bb3ae66c0aa94f9b61150e6d",
        "https://git.kernel.org/stable/c/47915e855fb38b42133e31ba917d99565f862154",
        "https://git.kernel.org/stable/c/4f949bc3913a6e3ce3b8574ac6ed1da8ec7a5ad1",
        "https://git.kernel.org/stable/c/90843d00dbc61220b66408ea0d8775cae9e51f70",
        "https://git.kernel.org/stable/c/ac44b4a3d6137489f8fa2e794b12e849c6b22eaa",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72237.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-72237",
        "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/2026/72xxx/CVE-2026-72237.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-72237",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 495964,
  "published_at": "2026-08-15T05:54:26.685+00:00"
}