GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

FKIE_CVE-2026-90001

Vulnerability from fkie_nvd - Published: 2026-09-16 11:17 - Updated: 2026-09-16 15:18
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: 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
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/401359684620145be710de97b87e1a47abfe1459
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/bfb7939788f3c8dd080a4dd81e38d625b35d194e
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c7f927aa8b55008ed5ea0814313d5dad771dcf3c
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "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": [
            {
              "lessThan": "401359684620145be710de97b87e1a47abfe1459",
              "status": "affected",
              "version": "ebc0d8093e8c97de459615438edefad1a4ac352c",
              "versionType": "git"
            },
            {
              "lessThan": "c7f927aa8b55008ed5ea0814313d5dad771dcf3c",
              "status": "affected",
              "version": "ebc0d8093e8c97de459615438edefad1a4ac352c",
              "versionType": "git"
            },
            {
              "lessThan": "bfb7939788f3c8dd080a4dd81e38d625b35d194e",
              "status": "affected",
              "version": "ebc0d8093e8c97de459615438edefad1a4ac352c",
              "versionType": "git"
            },
            {
              "lessThan": "9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0",
              "status": "affected",
              "version": "ebc0d8093e8c97de459615438edefad1a4ac352c",
              "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-rc2",
              "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\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."
    }
  ],
  "id": "CVE-2026-90001",
  "lastModified": "2026-09-16T15:18:23.880",
  "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": "2026-09-16T11:17:11.700",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/401359684620145be710de97b87e1a47abfe1459"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9cdc7e6dc7a99ad7311ad5e7c145f2b9ce4e24b0"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/bfb7939788f3c8dd080a4dd81e38d625b35d194e"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c7f927aa8b55008ed5ea0814313d5dad771dcf3c"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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