{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64004",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64004"
  ],
  "published": "2026-07-19T14:56:29Z",
  "summary": "net/iucv: fix locking in .getsockopt",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix locking in .getsockopt\n\nMirror iucv_sock_setsockopt() and wrap the whole switch in\nlock_sock()/release_sock(). The pre-existing SO_MSGLIMIT-only lock\nbecomes redundant and is removed.\n\nAny AF_IUCV HIPER user can potentially crash the kernel by racing\nrecvmsg() with getsockopt(SO_MSGSIZE): the SO_MSGSIZE arm dereferences\niucv->hs_dev->mtu after iucv_sock_close() (called from the racing\nrecvmsg()) has set hs_dev to NULL, producing a NULL pointer dereference\noops.",
  "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": "6.1.176",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64004"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/884eb247b74d86db97e3a37f0d6fc8e1e83590dd"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/45bb8de8c95d8899f4b8f61bd9bceb8132af73cb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1fc30bd4e55e2dd622d2d366cecd732c1841bbee"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cd691beafea0dd779e69e81ccc26b0ab50efcb5e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6e792b8dd3002bbc4136745928a9605df1a72b8a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9817369243380e287ebe5525411557eaa3aa2a79"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/69554adc7a6fa04ede3ad7512321d83748e3c920"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3589d20a666caf30ad100c960a2de7de390fce88"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The flaw is reached through the getsockopt(2) syscall on an AF_IUCV HIPER socket; the generic socket layer does not acquire the socket lock before calling iucv_sock_getsockopt(), so exploitation requires local access to the socket file descriptor.\nAC:L - The attacker controls both sides of the race by running concurrent getsockopt(SO_MSGSIZE) and recvmsg()/close() threads on the same socket, making the window reliably winnable without external timing luck.\nPR:L - The fix commit explicitly states any AF_IUCV HIPER user can trigger the crash, and iucv_sock_create imposes no capability or root requirement beyond creating and binding a HiperSockets AF_IUCV socket on s390.\nUI:N - Exploitation requires no action from any other user; the attacker races their own syscalls on a socket they control.\nS:U - The impact is a kernel oops or crash within the same kernel security boundary, with no cross-VM, cross-container, or IOMMU boundary crossing.\nC:H - The unlocked TOCTOU between the hs_dev NULL check and dereference races with dev_put() freeing the net_device, creating a use-after-free read whose mtu field is copied to userspace via copy_to_user.\nI:H - Use-after-free on a freed net_device structure in kernel heap memory is a memory corruption primitive that could be further leveraged for control-flow hijacking, and per kernel CVSS guidance UAF bugs warrant High integrity impact.\nA:H - Successful exploitation produces a NULL pointer dereference oops or kernel panic, causing complete loss of availability on the affected IBM Z LPAR or guest."
    }
  }
}