CVE-2026-90001 (GCVE-0-2026-90001)
Vulnerability from cvelistv5
Published
2026-09-16 10:33
Modified
2026-10-19 08:56
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: HID: bpf: serialize device reference release in struct_ops destroy path __hid_bpf_ops_destroy_device() and hid_bpf_unreg() can race on the same registration reference, double-putting struct hid_device and freeing it while hid_destroy_device() still uses it. Serialize the remove/NULL decision under hdev->bpf.prog_list_lock so exactly one path releases each registration reference: unreg re-checks ops->hdev under the lock and returns without putting when the destroy path already cleared it; all put_device() calls happen after the lock is dropped, which is safe because a concurrent unreg then observes ops->hdev == NULL under the lock. Background: each successful attach (hid_bpf_ops_reg) acquires one device reference (hid_get_device()). Two paths can release it: - device destruction: hid_destroy_device() -> hid_bpf_destroy_device() -> __hid_bpf_ops_destroy_device(), which walks hdev->bpf.prog_list under rcu_read_lock() and drops one reference per attached program; - BPF link release: bpf map delete (no BPF_F_LINK) synchronously calls st_ops->unreg() -> hid_bpf_unreg(), which drops the reference for its own registration. The coordination handshake (e->hdev = NULL on the destroy side vs "if (!hdev) return" on the unreg side) is a TOCTOU check: the two paths run under different lock domains (rcu_read_lock vs prog_list_lock), so a concurrent unreg can read ops->hdev as non-NULL, block on prog_list_lock, and then proceed while the destroy traversal executes - both paths then drop the same reference. The refcount reaches zero legitimately (each decrement is individually valid), so no refcount_t saturation fires: the device is simply freed while the transport is still inside hid_destroy_device(), and subsequent teardown touches freed memory. The fix serializes the remove/NULL decision under prog_list_lock on both sides and moves the destroy-side puts outside the lock. With the lock held, plain reads/writes of ops->hdev are sufficient; no READ_ONCE/WRITE_ONCE are added, keeping the patch minimal. Unlocked-read safety: the unlocked read of ops->hdev at the top of hid_bpf_unreg() cannot touch a freed device, because the unreg path itself still holds this registration's reference (released only by its own hid_put_device() after the lock is dropped), and a destroy traversal that already cleared ops->hdev makes the lock-internal re-check return early without any put. At most one of the two paths releases each registration reference.
References
Impacted products
Vendor Product Version
Linux Linux Version: ebc0d8093e8c97de459615438edefad1a4ac352c
Version: ebc0d8093e8c97de459615438edefad1a4ac352c
Version: ebc0d8093e8c97de459615438edefad1a4ac352c
Version: ebc0d8093e8c97de459615438edefad1a4ac352c
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/hid/bpf/hid_bpf_struct_ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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              "status": "affected",
              "version": "ebc0d8093e8c97de459615438edefad1a4ac352c",
              "versionType": "git"
            },
            {
              "lessThan": "c7f927aa8b55008ed5ea0814313d5dad771dcf3c",
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              "versionType": "git"
            },
            {
              "lessThan": "9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0",
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              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/hid/bpf/hid_bpf_struct_ops.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.11"
            },
            {
              "lessThan": "6.11",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.51",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.110",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.51",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.5",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "6.11",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nHID: bpf: serialize device reference release in struct_ops destroy path\n\n__hid_bpf_ops_destroy_device() and hid_bpf_unreg() can race on the\nsame registration reference, double-putting struct hid_device and\nfreeing it while hid_destroy_device() still uses it.  Serialize the\nremove/NULL decision under hdev-\u003ebpf.prog_list_lock so exactly one\npath releases each registration reference: unreg re-checks ops-\u003ehdev\nunder the lock and returns without putting when the destroy path\nalready cleared it; all put_device() calls happen after the lock is\ndropped, which is safe because a concurrent unreg then observes\nops-\u003ehdev == NULL under the lock.\n\nBackground: each successful attach (hid_bpf_ops_reg) acquires one\ndevice reference (hid_get_device()).  Two paths can release it:\n\n- device destruction: hid_destroy_device() -\u003e hid_bpf_destroy_device()\n  -\u003e __hid_bpf_ops_destroy_device(), which walks hdev-\u003ebpf.prog_list\n  under rcu_read_lock() and drops one reference per attached program;\n- BPF link release: bpf map delete (no BPF_F_LINK) synchronously calls\n  st_ops-\u003eunreg() -\u003e hid_bpf_unreg(), which drops the reference for\n  its own registration.\n\nThe coordination handshake (e-\u003ehdev = NULL on the destroy side vs\n\"if (!hdev) return\" on the unreg side) is a TOCTOU check: the two\npaths run under different lock domains (rcu_read_lock vs\nprog_list_lock), so a concurrent unreg can read ops-\u003ehdev as\nnon-NULL, block on prog_list_lock, and then proceed while the\ndestroy traversal executes - both paths then drop the same\nreference.  The refcount reaches zero legitimately (each decrement\nis individually valid), so no refcount_t saturation fires: the\ndevice is simply freed while the transport is still inside\nhid_destroy_device(), and subsequent teardown touches freed memory.\n\nThe fix serializes the remove/NULL decision under prog_list_lock on\nboth sides and moves the destroy-side puts outside the lock.  With\nthe lock held, plain reads/writes of ops-\u003ehdev are sufficient; no\nREAD_ONCE/WRITE_ONCE are added, keeping the patch minimal.\n\nUnlocked-read safety: the unlocked read of ops-\u003ehdev at the top of\nhid_bpf_unreg() cannot touch a freed device, because the unreg path\nitself still holds this registration\u0027s reference (released only by\nits own hid_put_device() after the lock is dropped), and a destroy\ntraversal that already cleared ops-\u003ehdev makes the lock-internal\nre-check return early without any put.  At most one of the two\npaths releases each registration reference."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - HID-BPF attach and unreg are reached only through local bpf() syscalls (BPF_MAP_TYPE_STRUCT_OPS / BPF_PROG_TYPE_STRUCT_OPS). Concurrent hid_destroy_device() is also local (uhid UHID_DESTROY/close or HID teardown), not a network or adjacent-radio packet path.\nAC:L - The attacker controls both sides of the TOCTOU race: attach HID-BPF, then concurrently delete the struct_ops map (hid_bpf_unreg) and destroy the HID device (e.g. uhid close). Destroy never took prog_list_lock, so unreg does not block on it and the double-put is reliably hittable.\nPR:L - Loading STRUCT_OPS maps/programs requires CAP_BPF and CAP_PERFMON, which can be delegated via BPF tokens into user namespaces rather than init-namespace root. /dev/uhid is also granted to the seat user on typical desktop systems, so real root is not required.\nUI:N - The attacker creates their own uhid HID device, loads and attaches HID-BPF struct_ops, then races map delete against device destroy in their own processes. No victim action such as plugging in hardware or mounting a filesystem is required.\nS:U - The double-put use-after-free of struct hid_device stays inside the host kernel HID/BPF authority and is a standard local privilege-escalation primitive, not a VM, IOMMU, or sandbox boundary crossing.\nC:H - Double-putting struct hid_device frees it while hid_destroy_device() still uses it. Use-after-free of this large kobject, which holds driver callbacks and pointers, enables an attacker-controlled kernel memory read primitive.\nI:H - The same use-after-free lets the attacker reclaim the freed hid_device via heap spray and corrupt ll_driver/hiddev function pointers or adjacent heap objects, yielding arbitrary kernel writes and control-flow hijacking.\nA:H - Even without full exploitation, dropping the hid_device refcount to zero while hid_remove_device()/put_device() still run causes a kernel oops, panic, or hang on the subsequent use of freed memory."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:56:15.260Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/401359684620145be710de97b87e1a47abfe1459"
        },
        {
          "url": "https://git.kernel.org/stable/c/c7f927aa8b55008ed5ea0814313d5dad771dcf3c"
        },
        {
          "url": "https://git.kernel.org/stable/c/bfb7939788f3c8dd080a4dd81e38d625b35d194e"
        },
        {
          "url": "https://git.kernel.org/stable/c/9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0"
        }
      ],
      "title": "HID: bpf: serialize device reference release in struct_ops destroy path",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90001",
    "datePublished": "2026-09-16T10:33:12.063Z",
    "dateReserved": "2026-09-11T19:38:34.780Z",
    "dateUpdated": "2026-10-19T08:56:15.260Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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