{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-74378",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-74378"
  ],
  "published": "2026-08-15T06:04:33Z",
  "summary": "RDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/rxe: Fix TOCTOU heap overflow in get_srq_wqe\n\nget_srq_wqe() reads wqe->dma.num_sge from the shared receive queue\nbuffer, which is mapped into userspace. It validates num_sge against\nmax_sge, but then re-reads the same field to calculate the memcpy\nsize. A concurrent userspace thread can modify num_sge between\nvalidation and use, causing a heap buffer overflow when copying the\nWQE into qp->resp.srq_wqe.\n\nRead num_sge into a local variable and use it for both the bounds\ncheck and the size calculation.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/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": "6.1.178",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-74378"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/c8db0e5ab0b6c540214c46c56aaac7cbcb0967fe"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/e48daa94ad2d406225b73491fc935064716f0ec7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3cfa2a3adc51b7c57729961a03446962ff10e3d2"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/cd19a6345e3727adafafa5954b58b13c92e13b80"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/3e07ea9579dc9553d2285c26c2823931358aa3b8"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/02558c86b6b761063e9399e6b939984500327ef1"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b9800d7953d119bcc068c74587d48e4ba0313629"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/22b8fbded65b8c441b634a185f8da67657df6c50"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-14T12:06:03Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - Exploitation requires a local process with mmap write access to the SRQ receive queue shared with the kernel; although incoming RoCE/UDP packets trigger get_srq_wqe(), a remote peer cannot modify num_sge in the victim's userspace-mapped WQE buffer, so the TOCTOU overflow cannot be achieved from the network alone.\nAC:L - The attacker controls both sides of the race: a userspace thread that repeatedly rewrites num_sge in the mmap'd SRQ entry and the thread/process that posts recv WQEs and receives the triggering RoCE Send/Write packet, making the TOCTOU window reliably winnable without external timing luck.\nPR:L - An unprivileged local user with access to /dev/infiniband/uverbs can create an SRQ (mmap'd queue), associate a QP, and post recv buffers via ibverbs; rxe device setup via \"rdma link add type rxe\" is reachable with CAP_NET_ADMIN inside a user namespace (unshare -Urn).\nUI:N - No victim user interaction is required; the attacker operates their own malicious RDMA userspace process and can self-trigger the vulnerable responder path with RoCE request packets once SRQ/QP resources are configured.\nS:U - The heap overflow corrupts kernel memory within the rxe_qp responder context on the same host kernel, enabling local privilege escalation rather than crossing a VM, container, or IOMMU security boundary to impact a different authority.\nC:H - The attacker-controlled memcpy size causes an out-of-bounds copy from the mmap'd SRQ ring buffer and overflows the fixed qp->resp.srq_wqe kernel buffer, enabling adjacent kernel heap data disclosure and providing primitives that can be developed into arbitrary kernel memory reads.\nI:H - Overflowing qp->resp.srq_wqe corrupts subsequent fields in rxe_resp_info/rxe_qp (e.g., responder resource pointers and state), giving a kernel heap buffer overflow that can be leveraged for arbitrary kernel memory writes and local privilege escalation.\nA:H - Corrupting responder state inside rxe_qp can cause kernel oops/panic or wedged RDMA processing during packet handling; even failed exploitation attempts can crash the kernel through use of corrupted function pointers and queue state."
    }
  }
}