{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-45856",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-45856"
  ],
  "published": "2026-05-27T12:19:29Z",
  "summary": "RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send\n\nib_uverbs_post_send() uses cmd.wqe_size from userspace without any\nvalidation before passing it to kmalloc() and using the allocated\nbuffer as struct ib_uverbs_send_wr.\n\nIf a user provides a small wqe_size value (e.g., 1), kmalloc() will\nsucceed, but subsequent accesses to user_wr->opcode, user_wr->num_sge,\nand other fields will read beyond the allocated buffer, resulting in\nan out-of-bounds read from kernel heap memory. This could potentially\nleak sensitive kernel information to userspace.\n\nAdditionally, providing an excessively large wqe_size can trigger a\nWARNING in the memory allocation path, as reported by syzkaller.\n\nThis is inconsistent with ib_uverbs_unmarshall_recv() which properly\nvalidates that wqe_size >= sizeof(struct ib_uverbs_recv_wr) before\nproceeding.\n\nAdd the same validation for ib_uverbs_post_send() to ensure wqe_size\nis at least sizeof(struct ib_uverbs_send_wr).",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/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": "6.1.165",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-45856"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9b5ac1c15334d46c0dbd49d64a2257b929500163"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/01c9b152647dc70dc06a4a2eff86ebb3b3c76075"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bf1feed1a7886af945f92890493aefd2b5c9928a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/d533425ac1f2925b4fc3e4ed9b9d72362cb23475"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bf4454da8b1e712714628c0a0d6e7845bb40790a"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/bef70ff9841990658610512b4a18e4a88c9b4df6"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0"
    }
  ],
  "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": 7.1,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The vulnerable code is reached via write() on the local RDMA uverbs character device (/dev/infiniband/uverbs*) dispatched through UAPI_DEF_WRITE_IO; it is not reachable over any network.\nAC:L - The attacker fully controls cmd.wqe_size and can reliably trigger the OOB read by simply setting wqe_size=1 (or the WARN with a huge value); no uncontrolled conditions are involved.\nPR:L - An unprivileged local user with access to the RDMA uverbs device (the normal case on RDMA-enabled systems, and obtainable via Soft-RoCE) can open a context, create a QP, and issue POST_SEND; no real-root privilege is required.\nUI:N - The command is issued directly by the attacker via a syscall; no action by any other user is needed.\nS:U - The OOB read and resulting impact remain within the kernel's own security authority; no crossing of a security boundary (VM/IOMMU/sandbox) occurs.\nC:H - The bug reads ~48 bytes of kernel heap memory beyond the undersized allocation, and the leaked values (e.g. wr_id) are returned to userspace via completion polling, giving a repeatable kernel-heap information disclosure.\nI:N - The defect is purely an out-of-bounds read; num_sge is bounded by the sge_count check, so no kernel memory is modified and there is no write primitive.\nA:H - An excessively large wqe_size triggers a WARNING in the allocator (syzkaller-reported), which becomes a kernel panic under the common panic_on_warn hardening, causing denial of service."
    }
  }
}