---
id: CVE-2025-38593
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'

  Function 'hci_discovery_filter_clear()' frees 'uuids' array and then
  sets it to NULL
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  Bluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'

  Function 'hci_discovery_filter_clear()' frees 'uuids' array and then
  sets it to NULL. There is a…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-415
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 5.17, < 6.6.117'
  - 'linux_kernel >= 6.7, < 6.12.42'
  - 'linux_kernel >= 6.13, < 6.15.10'
  - 'linux_kernel >= 6.16, < 6.16.1'
patched:
  - linux_kernel 6.16.1
published: '2025-08-19'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T22:18:46.633'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-38593'
references:
  - url: 'https://git.kernel.org/stable/c/16852eccbdfaf41a666705e3f8be55cf2864c5ca'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2935e556850e9c94d7a00adf14d3cd7fe406ac03'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7ce9bb0b95fc280e9212b8922590c492ca1d9c39'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/86f3dcd1f331cfd4fd7ec88906955134ec51afbe'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a351ff6b8ecca4229afaa0d98042bead8de64799'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f8069f34c4c976786ded97498012225af87435d7'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
epss: 0.00177
epssPercentile: 0.07138
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-15T21:52:06.790277Z'
ingestedAt: '2026-10-15T22:48:25.513Z'
---

## Overview

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

Bluetooth: hci_sync: fix double free in 'hci_discovery_filter_clear()'

Function 'hci_discovery_filter_clear()' frees 'uuids' array and then
sets it to NULL. There is a tiny chance of the following race:

'hci_cmd_sync_work()'

 'update_passive_scan_sync()'

   'hci_update_passive_scan_sync()'

     'hci_discovery_filter_clear()'
       kfree(uuids);

       <-------------------------preempted-------------------------------->
                                           'start_service_discovery()'

                                             'hci_discovery_filter_clear()'
                                               kfree(uuids); // DOUBLE FREE

       <-------------------------preempted-------------------------------->

      uuids = NULL;

To fix it let's add locking around 'kfree()' call and NULL pointer
assignment. Otherwise the following backtrace fires:

[ ] ------------[ cut here ]------------
[ ] kernel BUG at mm/slub.c:547!
[ ] Internal error: Oops - BUG: 00000000f2000800 [#1] PREEMPT SMP
[ ] CPU: 3 UID: 0 PID: 246 Comm: bluetoothd Tainted: G O 6.12.19-kernel #1
[ ] Tainted: [O]=OOT_MODULE
[ ] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ ] pc : __slab_free+0xf8/0x348
[ ] lr : __slab_free+0x48/0x348
...
[ ] Call trace:
[ ]  __slab_free+0xf8/0x348
[ ]  kfree+0x164/0x27c
[ ]  start_service_discovery+0x1d0/0x2c0
[ ]  hci_sock_sendmsg+0x518/0x924
[ ]  __sock_sendmsg+0x54/0x60
[ ]  sock_write_iter+0x98/0xf8
[ ]  do_iter_readv_writev+0xe4/0x1c8
[ ]  vfs_writev+0x128/0x2b0
[ ]  do_writev+0xfc/0x118
[ ]  __arm64_sys_writev+0x20/0x2c
[ ]  invoke_syscall+0x68/0xf0
[ ]  el0_svc_common.constprop.0+0x40/0xe0
[ ]  do_el0_svc+0x1c/0x28
[ ]  el0_svc+0x30/0xd0
[ ]  el0t_64_sync_handler+0x100/0x12c
[ ]  el0t_64_sync+0x194/0x198
[ ] Code: 8b0002e6 eb17031f 54fffbe1 d503201f (d4210000)
[ ] ---[ end trace 0000000000000000 ]---

## Affected

- `linux_kernel >= 5.17, < 6.6.117`
- `linux_kernel >= 6.7, < 6.12.42`
- `linux_kernel >= 6.13, < 6.15.10`
- `linux_kernel >= 6.16, < 6.16.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 6.16.1`