{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53680",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53680"
  ],
  "published": "2025-10-07T15:23:56Z",
  "summary": "NFSD: Avoid calling OPDESC() with ops->opnum == OP_ILLEGAL",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nNFSD: Avoid calling OPDESC() with ops->opnum == OP_ILLEGAL\n\nOPDESC() simply indexes into nfsd4_ops[] by the op's operation\nnumber, without range checking that value. It assumes callers are\ncareful to avoid calling it with an out-of-bounds opnum value.\n\nnfsd4_decode_compound() is not so careful, and can invoke OPDESC()\nwith opnum set to OP_ILLEGAL, which is 10044 -- well beyond the end\nof nfsd4_ops[].",
  "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": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.24"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53680"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/50827896c365e0f6c8b55ed56d444dafd87c92c5"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a64160124d5a078be0c380b1e8a0bad2d040d3a1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/ffcbcf087581ae68ddc0a21460f7ecd4315bdd0e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f352c41fa718482979e7e6b71b4da2b718e381cc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/804d8e0a6e54427268790472781e03bc243f4ee3"
    }
  ],
  "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 defect is in nfsd's NFSv4 COMPOUND XDR decoder, driven directly by bytes a remote client sends to TCP/2049. Any host able to reach the NFS server can supply the malformed opnum.\nAC:L - Triggering requires only a single COMPOUND request carrying an opnum outside the legal range for the minorversion (e.g. 0, 1, 2, or anything above LAST_NFS42_OP); it is deterministic with no race, timing, or memory-layout dependency.\nPR:N - nfsd4_decode_compound() runs during RPC argument decode, before any export permission, filehandle, or NFSv4 state/authorization check in nfsd4_proc_compound(); with the default AUTH_SYS flavor no principal is authenticated, so an unauthenticated network peer reaches this code.\nUI:N - The attacker sends the malformed COMPOUND unilaterally; nothing is required of any local user or administrator on the server.\nS:U - The out-of-bounds pointer and any resulting fault stay within the kernel's own security authority on the NFS server, with no crossing of a VM, IOMMU, or sandbox boundary.\nC:N - Nothing read from the out-of-bounds address is ever encoded into the NFS reply \u2014 the descriptor fields are only tested as flags or used as a call target \u2014 and the offset is a hardcoded constant the attacker cannot steer, so no information is disclosed to the attacker.\nI:N - The bug only forms and stores an out-of-bounds read pointer; no attacker-controlled data is written anywhere and no kernel memory is modified.\nA:H - The wild pointer points roughly 550 KB past a const array in nfsd's module mapping, and any dereference of it (e.g. the indirect call OPDESC(op)->op_rsize_bop() in nfsd4_max_reply(), which is protected only by an easily-missed open-coded OP_ILLEGAL check) faults in an nfsd kthread and takes the NFS service down. A remote unauthenticated attacker can repeat the request at will, so the availability impact is scored High."
    }
  }
}