{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-98323",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-98323"
  ],
  "published": "2026-10-06T08:47:10Z",
  "summary": "RDMA/siw: Bound fragmented header copies by the remaining length",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/siw: Bound fragmented header copies by the remaining length\n\nsiw_get_hdr() can receive an extended DDP/RDMAP header across more than\none TCP callback. The first callback may receive most of the header,\nwhile the next one still limits the copy to hdrlen - MIN_DDP_HDR instead\nof the number of missing bytes. This makes the destination move past the\nend of the header and overwrite the receive state, including\nfpdu_part_rcvd. A later callback can then use a negative fpdu_part_rcvd\nvalue as a copy offset, which creates an OOB write.\n\nUse the number of header bytes already received when calculating the\nnext copy length.",
  "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": [
        "1:6.1.47-1+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": "6.1.189",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-98323"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2c6fbcf4bfac0b2b186acc8d91154c0fa24468a7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/af9f5b474a260ad23ffb9793d716a5e3bbce3b48"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/262dcd809723723ed8a4e05437ec7e9c21a8f17e"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/eb4d7a946970469b3ab0c762432bf161d5b0836c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/8628f8ebf41669302513fb3f0bf0eba38b226742"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b72dcfb9bf1f0f0147cda03dc59e4002a315067f"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e6bdfdf3bcb02d0d626a45e8c98b7e63d2fddf9d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9ff797e516dbc1ecb73701ec4c24055712d44411"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-10-07T06:50:27Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 9.8,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - The malformed input is the remote iWARP peer's own MPA/DDP/RDMAP header bytes on the siw TCP connection. The peer splits an extended header (e.g. RDMA Read Request, 44 bytes) across TCP segments, and siw_qp_llp_data_ready() -> tcp_read_sock() -> siw_tcp_rx_data() -> siw_get_hdr() parses them. The transport is routable TCP.\nAC:L - The peer fully controls TCP segmentation, so it can deterministically end a segment with fpdu_part_rcvd between 16 and hdrlen. The next segment then copies hdrlen-16 bytes at that offset. No race or state outside the attacker's control is involved beyond siw serving an iWARP listener.\nPR:N - Once the MPA exchange puts the QP in RTS, siw_get_hdr() parses every incoming FPDU header, and neither MPA nor DDP authenticates the peer. ULP authorisation (such as an nvmet-rdma host NQN check) only arrives in messages parsed by this same path, so the overflow fires before any credential check.\nUI:N - No victim action is needed. The attacker connects to the iWARP service and sends crafted fragmented FPDUs, and siw processes them in its sk_data_ready callback.\nS:U - The corruption is confined to kernel memory of the host running siw (struct siw_qp and its neighbours). That is the same security authority as the vulnerable component, with no VM or IOMMU boundary crossed.\nC:H - The overflow writes peer bytes over siw_rx_stream fields after hdr, including fpdu_part_rcvd. A negative fpdu_part_rcvd then makes skb_copy_bits() write to c_hdr plus an attacker-chosen offset. A controlled kernel write like this can be turned into arbitrary kernel memory disclosure.\nI:H - siw_get_hdr() copies up to hdrlen-17 attacker bytes past srx->hdr (27 for rreq), overwriting the receive state. The next callback uses the corrupted negative fpdu_part_rcvd as the destination offset of skb_copy_bits(), giving an out-of-bounds kernel write whose offset and data are attacker-controlled.\nA:H - Corrupting fpdu_part_rcvd/fpdu_part_rem and writing out of bounds from siw_qp crashes or panics the kernel. A remote peer can repeat this on every connection."
    }
  }
}