CVE-2026-98246 Bluetooth: hci_sync: Serialize local codec list cleanup
A race condition in the Linux kernel Bluetooth subsystem allows a local attacker to trigger a use-after-free, potentially causing a system crash or arbitrary code execution.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98246?
CVE-2026-98246 is an use after free vulnerability in Linux, published on 6 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sync: Serialize local codec list cleanup
hci_dev_close_sync() clears hdev->local_codecs after releasing hdev->lock. Codec list additions and both traversals in sco_sock_getsockopt() use that lock, but the close path does not. A close and BT_CODEC query can therefore interleave as follows:
hci_dev_close_sync() sco_sock_getsockopt() hci_dev_lock() fetch codec entry hci_codec_list_clear() kfree(entry) read entry->id
The reader then accesses an entry which the close path has freed. KASAN
BUG: KASAN: slab-use-after-free in sco_sock_getsockopt+0xfa0/0xfe0 Read of size 1 at addr ffff8881001c3450 Call Trace: sco_sock_getsockopt+0xfa0/0xfe0 do_sock_getsockopt+0x537/0x7b0 __sys_getsockopt+0xf2/0x170 Allocated by task 92: hci_codec_list_add.isra.0+0x2c/0x440 hci_read_codec_capabilities+0x224/0x590 hci_read_supported_codecs+0x2c2/0x640 Freed by task 92: kfree+0x131/0x3c0 hci_codec_list_clear+0xd8/0x160 hci_dev_close_sync+0x92a/0xfa0
Take hdev->lock around the clear operation at its existing point in the close path. This makes the clear wait for active readers and prevents a new traversal until the list is empty without changing teardown ordering.
Which versions are affected by CVE-2026-98246?
How do I fix CVE-2026-98246?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-98246 being exploited?
There is no known exploitation of CVE-2026-98246 in the wild and no public exploit code.
Sources
Also known as AZL-106437, BELL-CVE-2026-98246, DEBIAN-CVE-2026-98246, GHSA-4jxq-xw37-v6h5, UBUNTU-CVE-2026-98246.