{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2026-92508",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2026-92508"
  ],
  "published": "2026-09-17T16:10:40Z",
  "summary": "RDMA/core: Fix potential use after free in ib_free_cq()",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nRDMA/core: Fix potential use after free in ib_free_cq()\n\nWhen accessing a CQ via the netlink path the only synchronization\nmechanism for the said CQ is rdma_restrack_get().\nCurrently, rdma_restrack_del() is invoked at the end of\nib_free_cq(), which is too late, since by that point\nvendor-specific resources associated with the CQ might already be\nfreed. This can leave a short window where the CQ remains accessible\nthrough restrack, leading to a potential use-after-free.\n\nFix this by moving the rdma_restrack_del() call to be before the freeing\nof the vendor-specific resources ensuring that the CQ is removed from\nrestrack before its internal resources are released.\nThis guarantees that no new users hold references to a CQ that is in\nthe process of destruction.",
  "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": "6.1.188",
            "compiled_filter": false
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-92508"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/a804b162f9bc2b38b2ed1b4752eea9faadb1645b"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/91f8a17a22ab615a03743120e19935e731f28fb9"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/76f2cb4f721815c3b6262a6dc2151de88646924c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/b8dcca427096fc9c50f1b376847fea72bc842d31"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/9abea37942534eeb049335476178696b654b000c"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/43403fe45379c64fa6276e5a8ede44493e5d2d3d"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/29dc2f8e1c97372c2871a70088707933515fbd5b"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-09-18T17:55:42Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - The use side is a local NETLINK_RDMA RDMA_NLDEV_CMD_RES_CQ_GET handled by nldev_res_get_cq_doit/dumpit \u2192 res_get_common_doit/dumpit, which rdma_restrack_get()s a CQ still in the xarray while ib_free_cq() is destroying it. No remote protocol message carries the lookup; the accessor is a netlink syscall.\nAC:L - The attacker drives both sides of the race: one thread loops RDMA_NLDEV_CMD_RES_CQ_GET while another opens and drops kernel-ULP RDMA connections so ib_free_cq() runs (svc_rdma_free() or smbdirect_connection_destroy_qp()). That is not a victim-only timing window.\nPR:L - RDMA_NLDEV_CMD_RES_CQ_GET in nldev_cb_table has no RDMA_NL_ADMIN_PERM, and NETLINK_RDMA is created with NL_CFG_F_NONROOT_RECV, so an ordinary user can dump CQs. Kernel CQ teardown via /dev/infiniband/rdma_cm (ucma_misc mode 0666) also does not need init-namespace root.\nUI:N - The attacker sends the RDMA_NLDEV_CMD_RES_CQ_GET dumps and tears down their own kernel-ULP RDMA connections; no other user must mount a volume, open a device, or confirm an action.\nS:U - The UAF is of host-kernel CQ vendor state (ib_cq buffers freed in destroy_cq/pre_destroy_cq) and stays inside the same kernel authority; it is not a VM escape, IOMMU bypass, or guest-to-host boundary cross.\nC:H - c4iw_destroy_cq() \u2192 destroy_cq() dma_free_coherent()s chp->cq.queue before rdma_restrack_del(); a concurrent fill_res_cq_entry \u2192 c4iw_fill_res_cq_entry still indexes that queue, so the UAF reads freed CQ-ring memory.\nI:H - The same ib_free_cq() window lets fill_res_cq_entry use vendor CQ resources already released by destroy_cq/pre_destroy_cq (Chelsio queue pages; mlx5 destroy_cq_kernel CQ buffers). Reclaiming that heap object yields an arbitrary write and control-flow hijack.\nA:H - fill_res_cq_entry walking a CQ whose queue or HW context was already freed in ib_free_cq() (after pre_destroy_cq/destroy_cq, before rdma_restrack_del) oopses or panics the kernel even without a crafted exploit."
    }
  }
}