{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-64048",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-64048"
  ],
  "published": "2026-07-19T15:41:06Z",
  "summary": "net/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/smc: reject CHID-0 ACCEPT that matches an empty ism_dev slot\n\nOn the SMC-D client, slot 0 of ini->ism_dev[]/ini->ism_chid[] is\nreserved for an SMC-Dv1 device. smc_find_ism_v2_device_clnt()\npopulates V2 entries starting at index 1, so when no V1 device is\nselected slot 0 is left in its kzalloc()'ed state with ism_dev[0] ==\nNULL and ism_chid[0] == 0.\n\nsmc_v2_determine_accepted_chid() then matches the peer's CHID against\nthe array starting from index 0 using the CHID alone. A malicious\npeer replying to a SMC-Dv2-only proposal with d1.chid == 0 matches\nthe empty slot, ini->ism_selected becomes 0, and the subsequent\nism_dev[0]->lgr_lock dereference in smc_conn_create() faults at\noffsetof(struct smcd_dev, lgr_lock) == 0x68:\n\n  BUG: KASAN: null-ptr-deref in _raw_spin_lock_bh+0x79/0xe0\n  Write of size 4 at addr 0000000000000068 by task exploit/144\n  Call Trace:\n   _raw_spin_lock_bh\n   smc_conn_create (net/smc/smc_core.c:1997)\n   __smc_connect (net/smc/af_smc.c:1447)\n   smc_connect (net/smc/af_smc.c:1720)\n   __sys_connect\n   __x64_sys_connect\n   do_syscall_64\n\nRequire ism_dev[i] to be non-NULL before accepting a CHID match.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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": "6.1.175",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-64048"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/903f7688ffeb9b323d70652c01f554bd4ba2a3d6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/dd2f9dd83c68abd7ba7ded7075290b016cb7ecd0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/6927cacf2b10d4fa80c1a2d407512ef9397c59c6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d38ba387244e5c5f7db3e11ea98bc2c7beccb0c0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/53eb7bd09aace72fa17510d80e0caf5ca058c231"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/afa9036b8c9963947b487c36e332df6a42c96fcb"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/65edb3b0822cfe5041be8fbabebd57e2e5ad9f4e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/277740023def559a4a2ddc3e8e784ee37a0f16a9"
    }
  ],
  "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": 7.5,
      "cvss_v3_severity": "High",
      "scenario": "AV:N - The fault is triggered while processing a malicious CLC ACCEPT message received from a remote TCP peer during the SMC-D handshake; the attacker controls the server response over the network.\nAC:L - Once a victim with SMC-Dv2 hardware initiates an SMC connection, a malicious peer can reliably send `d1.chid == 0` in the CLC ACCEPT to match the empty reserved slot 0 without races or special timing.\nPR:N - No local privileges are required on the victim host; an unauthenticated remote attacker operating a malicious SMC server can crash connecting clients, and unprivileged users can create SMC sockets without capability checks.\nUI:N - Exploitation requires only that a victim application initiate a normal outbound SMC connection to the attacker's server, which occurs automatically in enterprise middleware without per-connection user action.\nS:U - The vulnerability causes a kernel crash on the victim host but does not cross a security boundary such as VM escape or sandbox breakout.\nC:N - The bug is a null pointer dereference when taking `ism_dev[0]->lgr_lock`; it causes an immediate kernel fault with no information disclosure.\nI:N - The attempted write at address 0x68 is a spinlock operation on a NULL `smcd_dev` pointer, not a controlled or arbitrary memory modification primitive.\nA:H - A successful trigger causes a kernel null pointer dereference (KASAN-reported oops/panic), crashing the affected system or at minimum the connecting process's kernel context."
    }
  }
}