{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53817",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53817"
  ],
  "published": "2025-12-09T00:01:55Z",
  "summary": "crypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: lib/mpi - avoid null pointer deref in mpi_cmp_ui()\n\nDuring NVMeTCP Authentication a controller can trigger a kernel\noops by specifying the 8192 bit Diffie Hellman group and passing\na correctly sized, but zeroed Diffie Hellamn value.\nmpi_cmp_ui() was detecting this if the second parameter was 0,\nbut 1 is passed from dh_is_pubkey_valid(). This causes the null\npointer u->d to be dereferenced towards the end of mpi_cmp_ui()",
  "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": "6.1.55",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53817"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fde791e8a96a64ea7b0ad2440e43586447a209c6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ae63e84ffda74267bf7277c38415ba38389229a0"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/61f5453e9706e99713825594e0c8f9031485fb5f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0fc7147c694394f8a8cbc19570c6bc918cac0906"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/67589d247909043e94d2dd5fb590958e0f99d58d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d3ad023a39f1127dcfd331c562673355dc078650"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/12ac013ad7ff0df066451e825801d805095b3776"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9e47a758b70167c9301d2b44d2569f86c7796f2d"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:24:39Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.5,
      "cvss_v3_severity": "High",
      "scenario": "AV:N - The vulnerable code is reached from NVMe-over-Fabrics (NVMe/TCP) DH-HMAC-CHAP authentication data received from a remote peer \u2014 either a malicious/MITM controller sending a Challenge to a host, or a remote initiator sending a Reply to an nvmet-tcp target on TCP/4420. The attacker-controlled bytes travel over the network with no locality requirement.\nAC:L - Triggering is fully deterministic: the attacker simply advertises a non-NULL DH group (e.g. ffdhe8192) and supplies a correctly sized but all-zero DH value, which makes mpi_read_raw_from_sgl() produce an MPI with nlimbs==0 and d==NULL. No race, no memory-layout dependency, and NVMe/TCP in-band authentication is a normal shipped configuration.\nPR:N - On the target side nvmet_auth_reply() computes the DH shared secret from the peer's DH value before the DH-HMAC-CHAP response HMAC is verified, so this is a pre-authentication code path; on the host side an impersonating/MITM controller needs no credentials to send the Challenge.\nUI:N - An nvmet-tcp target listens passively and the attacker drives the whole DH-HMAC-CHAP exchange; no local user action is required to trigger the oops.\nS:U - The NULL dereference crashes the kernel that is processing the authentication message; the impact stays within that kernel's own security authority with no boundary crossing.\nC:N - The fault is a read of address 0 (u->d[0]) that immediately oopses; no attacker-influenced memory is read back or returned to the peer, so no information is disclosed.\nI:N - The bug is a NULL pointer read, not a write or type confusion; nothing is corrupted and there is no primitive for modifying kernel memory or hijacking control flow.\nA:H - Dereferencing the NULL u->d produces a kernel oops in the NVMe auth work handler, killing the connection/worker and panicking the box under panic_on_oops, and it can be re-triggered on every new authentication attempt."
    }
  }
}