{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "c3bea3d2dc5358e05541527283279102383b0231"
            },
            {
              "fixed": "9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7"
            },
            {
              "fixed": "9b5ac1c15334d46c0dbd49d64a2257b929500163"
            },
            {
              "fixed": "01c9b152647dc70dc06a4a2eff86ebb3b3c76075"
            },
            {
              "fixed": "bf1feed1a7886af945f92890493aefd2b5c9928a"
            },
            {
              "fixed": "d533425ac1f2925b4fc3e4ed9b9d72362cb23475"
            },
            {
              "fixed": "bf4454da8b1e712714628c0a0d6e7845bb40790a"
            },
            {
              "fixed": "bef70ff9841990658610512b4a18e4a88c9b4df6"
            },
            {
              "fixed": "1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "5.0.0"
            },
            {
              "fixed": "5.10.252"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.202"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.165"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.128"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.75"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.14"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45856.json"
  },
  "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-\u003eopcode, user_wr-\u003enum_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 \u003e= 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).",
  "id": "CVE-2026-45856",
  "modified": "2026-08-12T03:51:30.207484508Z",
  "published": "2026-05-27T12:15:33.209Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/01c9b152647dc70dc06a4a2eff86ebb3b3c76075"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9b5ac1c15334d46c0dbd49d64a2257b929500163"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bef70ff9841990658610512b4a18e4a88c9b4df6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf1feed1a7886af945f92890493aefd2b5c9928a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bf4454da8b1e712714628c0a0d6e7845bb40790a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d533425ac1f2925b4fc3e4ed9b9d72362cb23475"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/45xxx/CVE-2026-45856.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-45856"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "RDMA/uverbs: Validate wqe_size before using it in ib_uverbs_post_send"
}