# CVE-2026-31500: Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

Status: published. Published: 2026-04-22. Updated: 2026-11-05.

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: btintel: serialize btintel_hw_error() with hci_req_sync_lock

btintel_hw_error() issues two __hci_cmd_sync() calls (HCI_OP_RESET
and Intel exception-info retrieval) without holding
hci_req_sync_lock().  This lets it race against
hci_dev_do_close() -> btintel_shutdown_combined(), which also runs
__hci_cmd_sync() under the same lock.  When both paths manipulate
hdev->req_status/req_rsp concurrently, the close path may free the
response skb first, and the still-running hw_error path hits a
slab-use-after-free in kfree_skb().

Wrap the whole recovery sequence in hci_req_sync_lock/unlock so it
is serialized with every other synchronous HCI command issuer.

Below is the data race report and the kasan report:

  BUG: data-race in __hci_cmd_sync_sk / btintel_shutdown_combined

  read of hdev->req_rsp at net/bluetooth/hci_sync.c:199
  by task kworker/u17:1/83:
   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
   btintel_hw_error+0x114/0x670 drivers/bluetooth/btintel.c:254
   hci_error_reset+0x348/0xa30 net/bluetooth/hci_core.c:1030

  write/free by task ioctl/22580:
   btintel_shutdown_combined+0xd0/0x360
    drivers/bluetooth/btintel.c:3648
   hci_dev_close_sync+0x9ae/0x2c10 net/bluetooth/hci_sync.c:5246
   hci_dev_do_close+0x232/0x460 net/bluetooth/hci_core.c:526

  BUG: KASAN: slab-use-after-free in
   sk_skb_reason_drop+0x43/0x380 net/core/skbuff.c:1202
  Read of size 4 at addr ffff888144a738dc
  by task kworker/u17:1/83:
   __hci_cmd_sync_sk+0x12f2/0x1c30 net/bluetooth/hci_sync.c:200
   __hci_cmd_sync+0x55/0x80 net/bluetooth/hci_sync.c:223
   btintel_hw_error+0x186/0x670 drivers/bluetooth/btintel.c:260

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < 7e041d0aad1d4d43d921ace052e04f4e2cacaed3 (affected, git); ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < 5f84e845648dfa86e42de5487f1a774b42f0444d (affected, git); ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < e10a4cb72468686ffbe8bb2b0520e37f6be1a0c5 (affected, git); ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < 66696648af477dc87859e5e4b607112f5f29d010 (affected, git); ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < f7d84737663ad4a120d2d8ef1561a4df91282c2e (affected, git); ≥ 973bb97e5aee56edddaae3d5c96877101ad509c0; < 94d8e6fe5d0818e9300e514e095a200bd5ff93ae (affected, git). Source: CNA: Linux
- Linux / Linux: 4.3 (affected); ≥ 0; < 4.3 (unaffected, semver); ≥ 6.1.175; ≤ 6.1.* (unaffected, semver); ≥ 6.6.131; ≤ 6.6.* (unaffected, semver); ≥ 6.12.80; ≤ 6.12.* (unaffected, semver); ≥ 6.18.21; ≤ 6.18.* (unaffected, semver); ≥ 6.19.11; ≤ 6.19.* (unaffected, semver); ≥ 7.0; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux
- Siemens / SIMATIC S7-1500 TM MFP - GNU/Linux subsystem: ≥ 0; < * (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.13% as of 2026-11-05; percentile 2.27%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/7e041d0aad1d4d43d921ace052e04f4e2cacaed3 (CNA: Linux)

- https://git.kernel.org/stable/c/5f84e845648dfa86e42de5487f1a774b42f0444d (CNA: Linux)

- https://git.kernel.org/stable/c/e10a4cb72468686ffbe8bb2b0520e37f6be1a0c5 (CNA: Linux)

- https://git.kernel.org/stable/c/66696648af477dc87859e5e4b607112f5f29d010 (CNA: Linux)

- https://git.kernel.org/stable/c/f7d84737663ad4a120d2d8ef1561a4df91282c2e (CNA: Linux)

- https://git.kernel.org/stable/c/94d8e6fe5d0818e9300e514e095a200bd5ff93ae (CNA: Linux)

- https://cert-portal.siemens.com/productcert/html/ssa-784472.html (ADP: siemens-SADP)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-31500; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-31500; retrieved 2026-11-05; source updated Not reported

Revision: f93777fa4b6ca4d28e79ae61479dc7181dbab5b5884867cb766fc595ca5afa2d

Canonical: https://y2.dev/cve/CVE-2026-31500

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