{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-81016",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-81016"
  ],
  "published": "2026-09-11T19:47:07Z",
  "summary": "platform/x86/amd/pmc: Propagate SMU errors and validate S2D address",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nplatform/x86/amd/pmc: Propagate SMU errors and validate S2D address\n\namd_stb_s2d_init() discards the return value of several S2D SMU commands.\nWhen the SMU refuses a command (e.g. \"SMU cmd failed. err: 0xff\") the\nfailure is only noticed indirectly - if at all - and reported as -EIO,\nmasking the real error.\n\nMore seriously, the S2D_PHYS_ADDR_LOW/HIGH return values are ignored, so\non failure phys_addr_low/hi are left uninitialised and the assembled\naddress is passed straight to devm_ioremap().  When the SMU leaves them at\nzero this maps physical address 0 and trips the ioremap-on-RAM warning:\n\n  amd_pmc AMDI000B:00: SMU cmd failed. err: 0xff\n  ioremap on RAM at 0x0000000000000000 - 0x0000000000ffffff\n  WARNING: CPU: 13 PID: 4592 at arch/x86/mm/ioremap.c:...\n\nCheck the return value of each SMU command and propagate it, and reject a\nzero physical address before calling devm_ioremap().",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.47-1+rpt4"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-2712",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v6",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l",
            "binary_version": "1:6.1.47-1+rpt4"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi3-rpi-v8",
            "binary_version": "1:6.1.47-1+rpt4"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.47-1+rpt4": {
            "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e",
            "upstream_version": "6.1.47",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": null,
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-81016"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/638e1ca5d4e2b4fdbb209db64926d013b34f3b79"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8178f59d76570b152d836bde07f5997f15861f04"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/775d4cde1f9737796ce7d8393521e9e8c5b49891"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0225c1d637687b03726f00ac65b6def843d2c464"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-10-03T11:04:09Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.7,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - amd_stb_s2d_init() runs from amd_pmc_probe() on the AMD PMC ACPI platform driver (AMDI0005\u2013AMDI000C and related IDs) during local device bind or module load; the SMU mailbox commands and devm_ioremap() are not reachable from network, Bluetooth, Wi-Fi, or USB packet paths.\nAC:L - On affected AMD platforms where SMU accepts S2D_TELEMETRY_SIZE but rejects S2D_PHYS_ADDR_LOW/HIGH (observed err 0xff), ignored failures leave phys_addr_low/hi uninitialized or zero and the subsequent ioremap is deterministic; stack zeroing makes address 0 reliable, with no race or attacker-uncontrollable layout.\nPR:N - The SMU queries and devm_ioremap() execute automatically in amd_pmc_probe() during ACPI/udev bind with no capable() check; enable_stb=1 is the vulnerable STB debug deployment (kernel cmdline or modprobe), after which kernel context runs the path without a user account or namespace privilege.\nUI:N - No victim interaction is required; the invalid ioremap occurs during automatic amd_pmc probe at boot or module load when STB is enabled, before any debugfs open, mount, or other user action.\nS:U - The bad physical-address ioremap, kernel warning, and any subsequent STB debugfs copy occur entirely inside the host kernel PMC driver; this is not a VM escape, IOMMU/DMA boundary bypass, or other cross-authority breakout.\nC:H - Ignored SMU failures pass uninitialized phys_addr_low/hi to devm_ioremap() for up to 16MB (S2D_TELEMETRY_DRAMBYTES_MAX); a non-RAM physical address creates a mapping that amd_stb_debugfs_open_v2 copies to userspace via memcpy_fromio on the 0644 stb_read node, yielding a large physical-memory disclosure.\nI:N - The driver only memcpy_fromio()s the STB mapping and never writes through stb_virt_addr; ioremap of RAM at address 0 is rejected, and there is no out-of-bounds write, use-after-free, or other kernel integrity or control-flow primitive.\nA:H - devm_ioremap() of physical address 0 hits WARN_ONCE in arch/x86/mm/ioremap.c, which panics under panic_on_warn; when the mapping fails, stb_virt_addr stays NULL while debugfs stb_read remains, so a later open does memcpy_fromio(NULL) and oopses the kernel."
    }
  }
}