{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-74470",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-74470"
  ],
  "published": "2026-08-15T12:28:42Z",
  "summary": "scsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: scsi_debug: Fix REPORT ZONES alloc_len underflow OOB write\n\nresp_report_zones() sizes the reply buffer from the CDB allocation\nlength. The v3 fix rounds alloc_len up with ALIGN() before deriving the\ndescriptor count:\n\n\trep_max_zones = (ALIGN((u64)alloc_len, RZONES_DESC_HD) -\n\t\t\t RZONES_DESC_HD) >> ilog2(RZONES_DESC_HD);\n\tarr_len = (u64)RZONES_DESC_HD * (rep_max_zones + 1);\n\nFor alloc_len in 0xFFFFFFC1..0xFFFFFFFF, ALIGN() rounds up to\n0x100000000, so arr_len is 4 GB. On 32-bit, kzalloc()'s size_t is 32-bit\nand truncates 0x100000000 to 0; kzalloc(0) returns ZERO_SIZE_PTR, which\npasses the !arr check, and desc = arr + 64 is then dereferenced in the\nloop -> out-of-bounds write / panic.\n\nClamp rep_max_zones to devip->nr_zones. The loop already stops at\nsdebug_capacity (after nr_zones zones), so a report can never hold more\nthan nr_zones descriptors; the clamp does not change the report, it only\nbounds arr_len to (nr_zones + 1) * RZONES_DESC_HD, a real device\nproperty that can never reach 0x100000000.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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": "6.1.183",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-74470"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7b615fc139e35c81077046df44725c532f7e2404"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5d3e1d006bbb543259f9e31824caadbfff6a5465"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/49e5b25a0b74dbac595f122e5608fdce2918cc4e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/495058429ca55ab7fcc21977b63b92907ad68066"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2047ed09bf13453b7d6f9431b112ec07984dd69b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d6e6da6bc3b53231fac77ffab428da8173ee729c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/93dde0bf2f39a0f9f57fd610aa3201ce5b753433"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-23T12:46:35Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The bug is reached by sending a crafted ZONE IN REPORT ZONES SCSI CDB through local SG_IO/BSG ioctl on a scsi_debug zoned LUN; scsi_debug is a pseudo host simulator with no native network protocol handler.\nAC:L - Once scsi_debug is loaded in host-managed zoned mode, a single REPORT ZONES command with ALLOCATION LENGTH 1-63 reliably underflows rep_max_zones and forces heap writes past a tiny kzalloc buffer; no races or victim-dependent timing are required.\nPR:L - ZBC_IN is whitelisted in scsi_cmd_allowed() without CAP_SYS_RAWIO, so any local user who can open the scsi_debug /dev/sg or BSG node (e.g., disk group) can issue the malicious CDB; module load and zoned setup are environmental, not exploit-time privileges.\nUI:N - Exploitation requires only the attacker issuing SG_IO/BSG with a malicious REPORT ZONES CDB; no separate victim interaction such as mounting media or clicking a prompt is needed.\nS:U - The out-of-bounds write corrupts kernel heap memory in the same host kernel security authority; it is not a VM escape, IOMMU bypass, or other cross-boundary compromise.\nC:H - The kmalloc heap out-of-bounds write can corrupt adjacent slab objects and be groomed into arbitrary kernel memory disclosure primitives; per kernel guidance, exploitable out-of-bounds writes warrant High confidentiality impact.\nI:H - Attacker-controlled REPORT ZONES allocation length drives rep_max_zones and causes repeated 64-byte descriptor writes far beyond the allocated buffer, providing a kernel heap out-of-bounds write suitable for control-data corruption and privilege escalation.\nA:H - Writing zone descriptors from arr+64 when the buffer is smaller than 64 bytes immediately corrupts out-of-bounds kernel memory and commonly triggers KASAN faults, kernel oops, or panic, satisfying High availability impact."
    }
  }
}