{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-46043",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-46043"
  ],
  "published": "2026-05-27T12:59:23Z",
  "summary": "RDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Validate pad and ICRC before payload_size() in rxe_rcv\n\nrxe_rcv() currently checks only that the incoming packet is at least\nheader_size(pkt) bytes long before payload_size() is used.\n\nHowever, payload_size() subtracts both the attacker-controlled BTH pad\nfield and RXE_ICRC_SIZE from pkt->paylen:\n\n  payload_size = pkt->paylen - offset[RXE_PAYLOAD] - bth_pad(pkt)\n                 - RXE_ICRC_SIZE\n\nThis means a short packet can still make payload_size() underflow even\nif it includes enough bytes for the fixed headers. Simply requiring\nheader_size(pkt) + RXE_ICRC_SIZE is not sufficient either, because a\npacket with a forged non-zero BTH pad can still leave payload_size()\nnegative and pass an underflowed value to later receive-path users.\n\nFix this by validating pkt->paylen against the full minimum length\nrequired by payload_size(): header_size(pkt) + bth_pad(pkt) +\nRXE_ICRC_SIZE.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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-2026-46043"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c4376c672c3648d5bdc31dfffc329d07164f93c4"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5fedefec757192dcaad29a664ac332c7601be144"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2c0d71ef12f46c57d37bc571f3f2797db7eb50cc"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/2fd4f8b749309a61c3f3f88ee8891d94f79e1240"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/f83519a4c122c9c7a850a2197648a9ff4c67c520"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9b924f3a26b21330a837cfe72e819b6393bbeeaa"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e8ee0e792d475b1067c199ef0af1b6221fa6f43d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/7244491dab347f648e661da96dc0febadd9daec3"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T13:16:28Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 9.1,
      "cvss_v3_severity": "Critical",
      "scenario": "AV:N - The vulnerable code processes RoCEv2 packets received over UDP/IP (port 4791) from a remote peer; `pkt->paylen` is derived directly from the attacker-controlled UDP length header field.\nAC:L - A single crafted packet with `paylen` at the header-size boundary and a non-zero BTH pad deterministically underflows `payload_size()`; the resulting ~2\u2076\u2074-byte read reliably runs off the buffer with no race or unknowable memory layout required.\nPR:N - A remote, unauthenticated attacker triggers it; via the multicast path `hdr_check()` returns success with no QP, so `rxe_icrc_check()` performs the OOB read with no established connection or credentials.\nUI:N - The packet is processed automatically in the receive path on arrival; no victim action is required.\nS:U - The fault and its impact are confined to the kernel's own memory/security scope; there is no crossing of a VM, IOMMU, or sandbox boundary.\nC:H - The integer underflow produces an unbounded out-of-bounds read length passed to the CRC/copy routines; per the rubric an unbounded OOB read is High confidentiality impact.\nI:N - The underflow is used purely as a read length; the downstream copy/write consumers are guarded by length checks and a negative truncated length makes the copy a no-op, so no memory is modified.\nA:H - The near-2\u2076\u2074-byte out-of-bounds read in `rxe_crc32()` walks off the skb buffer into unmapped memory, causing a kernel oops/panic."
    }
  }
}