In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_core: Fix use-after-free in vhci_flush()
syzbot reported use-after-free in vhci_flush() without repro. [0]
From the splat, a thread close()d a vhci file descriptor while its device was being used by iotcl() on another thread.
Once the last fd refcnt is released, vhci_release() calls hci_unregister_dev(), hci_free_dev(), and kfree() for struct vhci_data, which is set to hci_dev->dev->driver_data.
The problem is that there is no synchronisation after unlinking hdev from hci_dev_list in hci_unregister_dev(). There might be another thread still accessing the hdev which was fetched before the unlink operation.
We can use SRCU for such synchronisation.
Let's run hci_dev_reset() under SRCU and wait for its completion in hci_unregister_dev().
Another option would be to restore hci_dev->destruct(), which was removed in commit 587ae086f6e4 ("Bluetooth: Remove unused hci-destruct cb"). However, this would not be a good solution, as we should not run hci_unregister_dev() while there are in-flight ioctl() requests, which could lead to another data-race KCSAN splat.
Note that other drivers seem to have the same problem, for exmaple, virtbt_remove().
[0]: BUG: KASAN: slab-use-after-free in skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline] BUG: KASAN: slab-use-after-free in skb_queue_purge_reason+0x99/0x360 net/core/skbuff.c:3937 Read of size 8 at addr ffff88807cb8d858 by task syz.1.219/6718
CPU: 1 UID: 0 PID: 6718 Comm: syz.1.219 Not tainted 6.16.0-rc1-syzkaller-00196-g08207f42d3ff #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 Call Trace: <TASK> dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0xd2/0x2b0 mm/kasan/report.c:521 kasan_report+0x118/0x150 mm/kasan/report.c:634 skb_queue_empty_lockless include/linux/skbuff.h:1891 [inline] skb_queue_purge_reason+0x99/0x360 net/core/skbuff.c:3937 skb_queue_purge include/linux/skbuff.h:3368 [inline] vhci_flush+0x44/0x50 drivers/bluetooth/hci_vhci.c:69 hci_dev_do_reset net/bluetooth/hci_core.c:552 [inline] hci_dev_reset+0x420/0x5c0 net/bluetooth/hci_core.c:592 sock_do_ioctl+0xd9/0x300 net/socket.c:1190 sock_ioctl+0x576/0x790 net/socket.c:1311 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:907 [inline] __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fcf5b98e929 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fcf5c7b9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fcf5bbb6160 RCX: 00007fcf5b98e929 RDX: 0000000000000000 RSI: 00000000400448cb RDI: 0000000000000009 RBP: 00007fcf5ba10b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fcf5bbb6160 R15: 00007ffd6353d528 </TASK>
Allocated by task 6535: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __kmalloc_cache_noprof+0x230/0x3d0 mm/slub.c:4359 kmalloc_noprof include/linux/slab.h:905 [inline] kzalloc_noprof include/linux/slab.h:1039 [inline] vhci_open+0x57/0x360 drivers/bluetooth/hci_vhci.c:635 misc_open+0x2bc/0x330 drivers/char/misc.c:161 chrdev_open+0x4c9/0x5e0 fs/char_dev.c:414 do_dentry_open+0xdf0/0x1970 fs/open.c:964 vfs_open+0x3b/0x340 fs/open.c:1094 do_open fs/namei.c:3887 [inline] path_openat+0x2ee5/0x3830 fs/name ---truncated---
CVSS Details
- CVSS 3.1 Base Score: 7.8
- CVSS 3.1 Vector: (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Alma_linux | — | Upgrade rvUpgrade kernel-debugUpgrade kernel-rt-kvmUpgrade kernel-64k-debug-modules-coreUpgrade kernel-rt-debug-modulesUpgrade bpftoolUpgrade kernel-rt-debug-modules-extraUpgrade kernel-rt-64k-debug-develUpgrade kernel-rt-debugUpgrade kernel-tools-libsUpgrade kernel-toolsUpgrade kernel-zfcpdump-modules-extraUpgrade python3-perfUpgrade kernel-rt-64k-debug-modules-coreUpgrade kernel-debug-uki-virtUpgrade kernel-rt-modules-extraUpgrade kernel-modules-extraUpgrade kernel-rt-modulesUpgrade kernel-64k-debug-modulesUpgrade kernel-uki-virtUpgrade kernel-rt-develUpgrade kernel-docUpgrade kernel-rt-coreUpgrade kernel-rt-64kUpgrade kernel-rtUpgrade kernel-64k-debug-develUpgrade kernel-rt-64k-coreUpgrade kernel-debug-coreUpgrade perfUpgrade kernel-rt-debug-coreUpgrade kernel-rt-debug-modules-coreUpgrade kernel-64k-debug-devel-matchedUpgrade kernel-64k-develUpgrade kernel-rt-64k-develUpgrade kernel-develUpgrade kernel-zfcpdump-devel-matchedUpgrade kernel-64k-modules-extraUpgrade kernel-coreUpgrade kernel-64k-modules-coreUpgrade kernel-64k-coreUpgrade kernel-debug-modules-coreUpgrade kernel-zfcpdump-develUpgrade kernel-cross-headersUpgrade kernel-headersUpgrade kernel-zfcpdump-modules-coreUpgrade kernel-tools-libs-develUpgrade kernel-64k-modulesUpgrade kernel-64k-debug-modules-extraUpgrade kernel-modulesUpgrade kernel-abi-stablelistsUpgrade kernel-uki-virt-addonsUpgrade kernel-rt-debug-develUpgrade kernel-zfcpdump-coreUpgrade kernel-rt-64k-debug-modulesUpgrade kernel-64k-devel-matchedUpgrade kernel-rt-64k-modulesUpgrade kernel-debug-develUpgrade rtlaUpgrade kernel-devel-matchedUpgrade kernel-rt-64k-debug-modules-extraUpgrade kernel-rt-64k-debugUpgrade kernel-rt-64k-modules-coreUpgrade kernel-64k-debugUpgrade kernel-rt-64k-modules-extraUpgrade kernel-rt-debug-kvmUpgrade kernel-debug-devel-matchedUpgrade kernel-zfcpdump-modulesUpgrade kernel-zfcpdumpUpgrade kernel-debug-modules-extraUpgrade kernel-64kUpgrade kernel-64k-debug-coreUpgrade kernel-modules-coreUpgrade kernel-rt-64k-debug-coreUpgrade kernel-debug-modulesUpgrade libperfUpgrade kernel-rt-modules-coreUpgrade kernel | Aug 19, 2025 | Aug 18, 2025 |
| Debian | — | Upgrade linuxUpgrade linux-6.1No solution exists | Jul 10, 2025 | Jul 10, 2025 |
| Oracle_linux | — | Upgrade kernel | Aug 19, 2025 | Jul 9, 2025 |
| Redhat_linux | — | Upgrade kernel-rtNo solution existsUpgrade kernel | Jul 10, 2025 | Jul 9, 2025 |
| Suse | — | Upgrade dtb-allwinnerUpgrade kernel-default-vdsoUpgrade cluster-md-kmp-rtUpgrade kernel-docs-htmlUpgrade kernel-rtUpgrade kernel-rt_debug-develUpgrade kernel-syms-azureUpgrade kernel-kvmsmallUpgrade kernel-default-optionalUpgrade kselftests-kmp-64kbUpgrade dtb-alteraUpgrade ocfs2-kmp-64kbUpgrade kernel-develUpgrade reiserfs-kmp-64kbUpgrade kernel-kvmsmall-vdsoUpgrade kernel-source-vanillaUpgrade dtb-freescaleUpgrade kernel-obs-buildUpgrade dlm-kmp-64kbUpgrade kernel-rt-optionalUpgrade kernel-64kbUpgrade gfs2-kmp-azureUpgrade gfs2-kmp-rtUpgrade kernel-rt-vdsoUpgrade kernel-devel-azureUpgrade kernel-zfcpdumpUpgrade gfs2-kmp-defaultUpgrade kernel-debug-vdsoUpgrade kernel-source-rtUpgrade kselftests-kmp-azureUpgrade dtb-lgUpgrade kernel-rt-extraUpgrade gfs2-kmp-64kbUpgrade dtb-hisiliconUpgrade dtb-qcomUpgrade kernel-64kb-optionalUpgrade kernel-azure-optionalUpgrade cluster-md-kmp-azureUpgrade kernel-azureUpgrade dtb-amdUpgrade dtb-caviumUpgrade ocfs2-kmp-defaultUpgrade dtb-marvellUpgrade dtb-exynosUpgrade kernel-debug-develUpgrade ocfs2-kmp-azureUpgrade dtb-appleUpgrade kernel-default-livepatchUpgrade dtb-amazonUpgrade kernel-default-develUpgrade dtb-broadcomUpgrade kernel-azure-extraUpgrade kernel-azure-develUpgrade kernel-kvmsmall-develUpgrade kernel-debugUpgrade kernel-source-azureUpgrade kernel-sourceUpgrade dtb-renesasUpgrade kernel-obs-qaUpgrade dlm-kmp-rtUpgrade cluster-md-kmp-defaultUpgrade kselftests-kmp-rtUpgrade kernel-rt-livepatch-develUpgrade dlm-kmp-defaultUpgrade cluster-md-kmp-64kbUpgrade kselftests-kmp-defaultUpgrade kernel-64kb-develUpgrade ocfs2-kmp-rtUpgrade kernel-default-livepatch-develUpgrade dtb-nvidiaUpgrade dtb-apmUpgrade kernel-default-manUpgrade kernel-defaultUpgrade kernel-64kb-extraUpgrade reiserfs-kmp-defaultUpgrade reiserfs-kmp-azureUpgrade kernel-syms-rtUpgrade kernel-rt_debug-vdsoUpgrade dtb-sprdUpgrade dtb-socionextUpgrade reiserfs-kmp-rtUpgrade kernel-docsUpgrade kernel-default-extraUpgrade kernel-default-base-rebuildUpgrade kernel-azure-vdsoUpgrade dtb-armUpgrade kernel-rt_debugUpgrade kernel-devel-rtUpgrade kernel-default-baseUpgrade dtb-mediatekUpgrade dlm-kmp-azureUpgrade kernel-symsUpgrade kernel-rt-develUpgrade dtb-rockchipUpgrade dtb-xilinxUpgrade kernel-macrosUpgrade dtb-amlogic | Dec 5, 2025 | Aug 27, 2025 |
| Ubuntu | — | Upgrade linux-image-nvidia-tegra-igx-5.15Upgrade linux-image-realtime-hwe-22.04Upgrade linux-image-6.8.0-1046-aws-fipsUpgrade linux-image-6.8.0-1047-raspiUpgrade linux-image-6.8.0-100-lowlatency-64kUpgrade linux-image-azure-6.14Upgrade linux-image-5.15.0-1112-gcpUpgrade linux-image-nvidiaUpgrade linux-image-5.15.0-1112-aws-64kUpgrade linux-image-aws-64kUpgrade linux-image-6.8.0-1046-nvidiaUpgrade linux-image-oracle-lts-24.04Upgrade linux-image-6.8.0-2037-raspi-realtimeUpgrade linux-image-generic-64kUpgrade linux-image-6.8.0-1043-oracleUpgrade linux-image-5.15.0-1053-nvidia-tegra-igxUpgrade linux-image-oracle-64kUpgrade linux-image-oracleUpgrade linux-image-lowlatency-64kUpgrade linux-image-nvidia-tegra-5.15Upgrade linux-image-nvidia-tegra-igx-rtUpgrade linux-image-gkeUpgrade linux-image-oem-20.04Upgrade linux-image-aws-5.15Upgrade linux-image-fips-6.8Upgrade linux-image-genericUpgrade linux-image-generic-64k-hwe-22.04Upgrade linux-image-fips-5.15Upgrade linux-image-6.8.0-1030-gkeopUpgrade linux-image-6.8.0-1046-azureUpgrade linux-image-5.15.0-1075-xilinx-zynqmpUpgrade linux-image-generic-hwe-22.04Upgrade linux-image-oracle-6.8Upgrade linux-image-virtual-hwe-24.04Upgrade linux-image-oem-22.04cUpgrade linux-image-xilinxUpgrade linux-image-generic-6.8Upgrade linux-image-intelUpgrade linux-image-aws-64k-lts-22.04Upgrade linux-image-oem-24.04bUpgrade linux-image-6.14.0-1014-azureUpgrade linux-image-6.14.0-1018-gcpUpgrade linux-image-5.15.0-1117-azure-fdeUpgrade linux-image-6.8.0-1043-gkeUpgrade linux-image-6.8.0-1051-azureUpgrade linux-image-oem-20.04dUpgrade linux-image-azure-6.8Upgrade linux-image-6.8.0-1046-nvidia-lowlatency-64kUpgrade linux-image-kvm-5.15Upgrade linux-image-lowlatency-5.15Upgrade linux-image-lowlatency-64k-hwe-22.04Upgrade linux-image-6.8.0-100-fipsUpgrade linux-image-gcp-64k-6.8Upgrade linux-image-nvidia-lowlatency-6.8Upgrade linux-image-nvidia-5.15Upgrade linux-image-realtimeUpgrade linux-image-realtime-hwe-24.04Upgrade linux-image-oem-22.04Upgrade linux-image-virtual-hwe-22.04Upgrade linux-image-raspi-realtimeUpgrade linux-image-nvidia-64kUpgrade linux-image-6.14.0-1015-aws-64kUpgrade linux-image-azure-fde-lts-22.04Upgrade linux-image-gke-64k-6.8Upgrade linux-image-oem-24.04Upgrade linux-image-intel-iotgUpgrade linux-image-intel-iotg-5.15Upgrade linux-image-5.15.0-1112-aws-fipsUpgrade linux-image-lowlatency-64k-6.8Upgrade linux-image-gkeopUpgrade linux-image-oem-20.04bUpgrade linux-image-oem-20.04cUpgrade linux-image-gkeop-5.15Upgrade linux-image-azure-lts-22.04Upgrade linux-image-gcpUpgrade linux-image-6.14.0-1014-oemUpgrade linux-image-6.14.0-1014-realtimeUpgrade linux-image-5.15.0-1064-nvidia-tegraUpgrade linux-image-6.8.0-1046-nvidia-64kUpgrade linux-image-oracle-lts-22.04Upgrade linux-image-oem-24.04aUpgrade linux-image-raspi-realtime-6.8Upgrade linux-image-generic-64k-hwe-20.04Upgrade linux-image-lowlatency-64k-5.15Upgrade linux-image-xilinx-zynqmpUpgrade linux-image-gke-6.8Upgrade linux-image-generic-hwe-20.04Upgrade linux-image-azure-fips-6.8Upgrade linux-image-nvidia-tegraUpgrade linux-image-generic-hwe-24.04Upgrade linux-image-5.15.0-1109-oracleUpgrade linux-image-5.15.0-184-lowlatency-64kUpgrade linux-image-5.15.0-1107-intel-iotgUpgrade linux-image-6.8.0-1046-azure-fipsUpgrade linux-image-nvidia-lowlatency-64k-6.8Upgrade linux-image-aws-64k-6.14Upgrade linux-image-5.15.0-1053-nvidia-tegra-igx-rtUpgrade linux-image-6.8.0-1047-gcpUpgrade linux-image-realtime-5.15Upgrade linux-image-6.14.0-1007-azure-nvidiaUpgrade linux-image-oem-22.04bUpgrade linux-image-gcp-6.14Upgrade linux-image-5.15.0-186-generic-lpaeUpgrade linux-image-6.14.0-1015-awsUpgrade linux-image-nvidia-hwe-22.04Upgrade linux-image-aws-lts-24.04Upgrade linux-image-5.15.0-1107-nvidiaUpgrade linux-image-gcp-fips-6.8Upgrade linux-image-virtual-6.14Upgrade linux-image-generic-lpae-5.15Upgrade linux-image-virtualUpgrade linux-image-generic-lpae-hwe-20.04Upgrade linux-image-azure-fips-5.15Upgrade linux-image-intel-iot-realtimeUpgrade linux-image-nvidia-lowlatencyUpgrade linux-image-ibm-classicUpgrade linux-image-6.14.0-34-generic-64kUpgrade linux-image-6.14.0-1018-gcp-64kUpgrade linux-image-oracle-64k-lts-24.04Upgrade linux-image-5.15.0-1112-awsUpgrade linux-image-xilinx-zynqmp-5.15Upgrade linux-image-raspiUpgrade linux-image-gcp-64k-lts-24.04Upgrade linux-image-nvidia-tegra-rtUpgrade linux-image-nvidia-tegra-igxUpgrade linux-image-5.15.0-1117-azure-fipsUpgrade linux-image-awsUpgrade linux-image-oem-24.04cUpgrade linux-image-lowlatency-hwe-22.04Upgrade linux-image-intel-iot-realtime-5.15Upgrade linux-image-gkeop-6.8Upgrade linux-image-generic-64k-5.15Upgrade linux-image-gcp-fips-5.15Upgrade linux-image-5.15.0-1104-intel-iot-realtimeUpgrade linux-image-generic-64k-6.14Upgrade linux-image-gcp-64kUpgrade linux-image-gcp-5.15Upgrade linux-image-aws-fips-6.8Upgrade linux-image-aws-fipsUpgrade linux-image-6.8.0-100-lowlatencyUpgrade linux-image-5.15.0-1117-azureUpgrade linux-image-5.15.0-1111-realtimeUpgrade linux-image-5.15.0-1064-nvidia-tegra-rtUpgrade linux-image-oracle-6.14Upgrade linux-image-gke-64kUpgrade linux-image-generic-lpaeUpgrade linux-image-fipsUpgrade linux-image-aws-fips-5.15Upgrade linux-image-aws-64k-5.15Upgrade linux-image-6.8.1-1041-realtimeUpgrade linux-image-virtual-hwe-20.04Upgrade linux-image-virtual-5.15Upgrade linux-image-oracle-64k-6.14Upgrade linux-image-azure-cvmUpgrade linux-image-azure-nvidiaUpgrade linux-image-azure-nvidia-6.14Upgrade linux-image-6.14.0-1015-oracle-64kUpgrade linux-image-6.14.0-1016-raspiUpgrade linux-image-nvidia-tegra-rt-5.15Upgrade linux-image-gke-5.15Upgrade linux-image-aws-64k-lts-24.04Upgrade linux-image-6.8.0-1046-awsUpgrade linux-image-6.8.0-1043-gke-64kUpgrade linux-image-6.14.0-1015-oracleUpgrade linux-image-virtual-6.8Upgrade linux-image-realtime-6.8.1Upgrade linux-image-oracle-5.15Upgrade linux-image-nvidia-64k-6.8Upgrade linux-image-nvidia-6.8Upgrade linux-image-6.8.0-1047-gcp-fipsUpgrade linux-image-raspi-6.14Upgrade linux-image-lowlatencyUpgrade linux-image-6.8.0-1043-oracle-64kUpgrade linux-image-5.15.0-1112-gcp-fipsUpgrade linux-image-generic-64k-6.8Upgrade linux-image-azure-fipsUpgrade linux-image-6.8.0-1047-gcp-64kUpgrade linux-image-gcp-fipsUpgrade linux-image-5.15.0-1095-gkeopUpgrade linux-image-aws-lts-22.04Upgrade linux-image-lowlatency-6.8Upgrade linux-image-aws-64k-6.8Upgrade linux-image-raspi-6.8Upgrade linux-image-6.8.0-1044-ibmUpgrade linux-image-6.8.0-1023-xilinxUpgrade linux-image-ibmUpgrade linux-image-5.15.0-1108-gkeUpgrade linux-image-oracle-64k-6.8Upgrade linux-image-oem-6.14Upgrade linux-image-nvidia-lowlatency-64kUpgrade linux-image-ibm-6.8Upgrade linux-image-generic-64k-hwe-24.04Upgrade linux-image-gcp-lts-24.04Upgrade linux-image-gcp-6.8Upgrade linux-image-azure-fde-5.15Upgrade linux-image-azureUpgrade linux-image-aws-6.14Upgrade linux-image-5.15.0-186-genericUpgrade linux-image-5.15.0-184-lowlatencyUpgrade linux-image-5.15.0-1107-nvidia-lowlatencyUpgrade linux-image-5.15.0-1104-kvmUpgrade linux-image-generic-5.15Upgrade linux-image-gcp-lts-22.04Upgrade linux-image-azure-lts-24.04Upgrade linux-image-gcp-64k-6.14Upgrade linux-image-azure-5.15Upgrade linux-image-aws-6.8Upgrade linux-image-6.8.0-1046-aws-64kUpgrade linux-image-6.8.0-100-genericUpgrade linux-image-6.14.0-34-genericUpgrade linux-image-xilinx-6.8Upgrade linux-image-realtime-6.14Upgrade linux-image-oem-22.04dUpgrade linux-image-nvidia-lowlatency-5.15Upgrade linux-image-lowlatency-hwe-20.04Upgrade linux-image-ibm-5.15Upgrade linux-image-generic-6.14Upgrade linux-image-6.8.0-1046-nvidia-lowlatencyUpgrade linux-image-ibm-lts-24.04Upgrade linux-image-azure-fdeUpgrade linux-image-6.8.0-100-generic-64kUpgrade linux-image-5.15.0-186-generic-64kUpgrade linux-image-5.15.0-186-fipsUpgrade linux-image-5.15.0-1106-ibmUpgrade linux-image-oem-22.04aUpgrade linux-image-nvidia-tegra-igx-rt-5.15Upgrade linux-image-nvidia-64k-hwe-22.04Upgrade linux-image-kvmUpgrade linux-image-lowlatency-64k-hwe-20.04 | Jul 14, 2025 | Jul 9, 2025 |
| Vmware Photon_os | — | Use 'tdnf update' to upgrade all packages to the latest version. | Jul 27, 2026 | Jul 9, 2025 |
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