FKIE_CVE-2026-72112

Vulnerability from fkie_nvd - Published: 2026-08-15 06:21 - Updated: 2026-08-17 06:18
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: io_uring/bpf-ops: reject re-registration of an already-bound ops io_install_bpf() only rejects a second registration on the ctx side (ctx->bpf_ops) and sets the per-map back-pointer ops->priv unconditionally. The struct_ops link path never advances a map past BPF_STRUCT_OPS_STATE_READY, so the same io_uring_bpf_ops map can be registered more than once, and bpf_io_reg() re-resolves the target ring via fget(ops->ring_fd) on every call. A caller can therefore point the same ring_fd at a different io_ring_ctx between two BPF_LINK_CREATE calls. The second registration passes the ctx->bpf_ops check (the new ctx has none) and overwrites ops->priv, orphaning the first ctx. Teardown (io_eject_bpf()/bpf_io_unreg()) only reaches a ctx through ops->priv, so the orphaned ctx is never torn down: its ctx->loop_step keeps pointing into the struct_ops trampoline, which is freed once the map is gone. A later io_uring_enter() on the orphaned ring then calls the dangling ctx->loop_step from io_run_loop() -- a use-after-free of freed executable memory, reachable by a task with CAP_BPF + CAP_PERFMON. Reject registration when ops->priv is already set, as hid_bpf_reg() does for its struct_ops.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/0639ea767fe04c288a8d6cb826100fe3d95d4936
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3afc64c61ce906a04f073ca350b46de10e8302f9
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "io_uring/bpf-ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "0639ea767fe04c288a8d6cb826100fe3d95d4936",
              "status": "affected",
              "version": "98f37634b12b17ad5c56db8fb63cf9d7dc55d74c",
              "versionType": "git"
            },
            {
              "lessThan": "3afc64c61ce906a04f073ca350b46de10e8302f9",
              "status": "affected",
              "version": "98f37634b12b17ad5c56db8fb63cf9d7dc55d74c",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "io_uring/bpf-ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "7.1"
            },
            {
              "lessThan": "7.1",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nio_uring/bpf-ops: reject re-registration of an already-bound ops\n\nio_install_bpf() only rejects a second registration on the ctx side\n(ctx-\u003ebpf_ops) and sets the per-map back-pointer ops-\u003epriv\nunconditionally. The struct_ops link path never advances a map past\nBPF_STRUCT_OPS_STATE_READY, so the same io_uring_bpf_ops map can be\nregistered more than once, and bpf_io_reg() re-resolves the target ring\nvia fget(ops-\u003ering_fd) on every call. A caller can therefore point the\nsame ring_fd at a different io_ring_ctx between two BPF_LINK_CREATE\ncalls.\n\nThe second registration passes the ctx-\u003ebpf_ops check (the new ctx has\nnone) and overwrites ops-\u003epriv, orphaning the first ctx. Teardown\n(io_eject_bpf()/bpf_io_unreg()) only reaches a ctx through ops-\u003epriv, so\nthe orphaned ctx is never torn down: its ctx-\u003eloop_step keeps pointing\ninto the struct_ops trampoline, which is freed once the map is gone. A\nlater io_uring_enter() on the orphaned ring then calls the dangling\nctx-\u003eloop_step from io_run_loop() -- a use-after-free of freed\nexecutable memory, reachable by a task with CAP_BPF + CAP_PERFMON.\n\nReject registration when ops-\u003epriv is already set, as hid_bpf_reg()\ndoes for its struct_ops."
    }
  ],
  "id": "CVE-2026-72112",
  "lastModified": "2026-08-17T06:18:10.417",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-08-15T06:21:25.563",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/0639ea767fe04c288a8d6cb826100fe3d95d4936"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3afc64c61ce906a04f073ca350b46de10e8302f9"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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