{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53083",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53083"
  ],
  "published": "2025-05-02T15:56:53Z",
  "summary": "nfsd: don't replace page in rq_pages if it's a continuation of last page",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: don't replace page in rq_pages if it's a continuation of last page\n\nThe splice read calls nfsd_splice_actor to put the pages containing file\ndata into the svc_rqst->rq_pages array. It's possible however to get a\nsplice result that only has a partial page at the end, if (e.g.) the\nfilesystem hands back a short read that doesn't cover the whole page.\n\nnfsd_splice_actor will plop the partial page into its rq_pages array and\nreturn. Then later, when nfsd_splice_actor is called again, the\nremainder of the page may end up being filled out. At this point,\nnfsd_splice_actor will put the page into the array _again_ corrupting\nthe reply. If this is done enough times, rq_next_page will overrun the\narray and corrupt the trailing fields -- the rq_respages and\nrq_next_page pointers themselves.\n\nIf we've already added the page to the array in the last pass, don't add\nit to the array a second time when dealing with a splice continuation.\nThis was originally handled properly in nfsd_splice_actor, but commit\n91e23b1c3982 (\"NFSD: Clean up nfsd_splice_actor()\") removed the check\nfor it.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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": "6.1.22"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53083"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8235cd619db6e67f1d7d26c55f1f3e4e575c947d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/12eca509234acb6b666802edf77408bb70d7bfca"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/51ddb84baff6f09ad62b5999ece3ec172e4e3568"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/0101067f376eb7b9afd00279270f25d5111a091d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/27c934dd8832dd40fd34776f916dc201e18b319b"
    }
  ],
  "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": 9.8,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - The bug is in nfsd_splice_actor on the NFSv2/v3/v4 READ splice path, reached by sending NFS READ RPCs to the in-kernel NFS server over TCP/UDP port 2049 from a remote client; no local access is required.\nAC:L - A remote client fully controls READ offsets/lengths and can retry at will; real-world Android/Kodi clients reliably triggered the partial-page splice continuation that causes the duplicate insert and array overrun, with no race outside attacker influence.\nPR:N - Under typical AUTH_SYS/AUTH_UNIX exports the client self-asserts uid/gid with no cryptographic secret; any host permitted by the export list can LOOKUP/OPEN and issue READ with no server-verified privileges.\nUI:N - The attacking NFS client issues the READ requests itself; no action by any administrator or other user on the server is required.\nS:U - The overrun corrupts fields inside the server's svc_rqst within the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The OOB write corrupts rq_respages/rq_next_page and was observed to drive page/folio refcount underflow, creating a UAF-class primitive over page-cache objects that can be leveraged for arbitrary kernel memory disclosure.\nI:H - Unbounded svc_rqst_replace_page writes of page pointers past rq_pages overwrite adjacent kernel pointers and skew page refcounts, yielding an out-of-bounds write / UAF write primitive exploitable for control-flow hijack.\nA:H - Production reports show repeatable nfsd kthread GPFs in release_pages and VM_BUG_ON folio refcount underflow during splice READ cleanup, crashing or freezing the NFS server and requiring reboot."
    }
  }
}