CVE-2026-98458 Bluetooth: ISO: release unused CIS holds after channel attach
A use-after-free vulnerability in the Linux kernel Bluetooth ISO subsystem allows local attackers to cause denial of service or potentially execute code.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-98458?
CVE-2026-98458 is an use after free vulnerability in Linux, published on 18 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: ISO: release unused CIS holds after channel attach
hci_bind_cis() and hci_connect_cis() return one hci_conn hold for the ISO layer. A new channel association consumes that hold, which is eventually released by iso_conn_free().
There are two cases where iso_chan_add() does not create an association: it returns success when the socket is already attached to the same iso_conn, and it returns -EBUSY when another socket is attached. The hold returned for the current call is unused in both cases. This occurs when deferred setup calls iso_connect_cis() again for its existing socket, or when another socket attempts to reuse the CIS.
Detect the idempotent case while the connection is locked and release the unused hold after iso_chan_add(). Also release it on -EBUSY. Do not drop it for other errors: a newly allocated iso_conn releases the transferred hold when its last temporary reference is put.
Which versions are affected by CVE-2026-98458?
How do I fix CVE-2026-98458?
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-2026-98458 being exploited?
There is no known exploitation of CVE-2026-98458 in the wild and no public exploit code.
Sources
Also known as AZL-109373, BELL-CVE-2026-98458, DEBIAN-CVE-2026-98458, GHSA-9rg4-gm9p-59qp, UBUNTU-CVE-2026-98458.