CVE-2026-98459 Bluetooth: ISO: balance the parent hold in hci_bind_bis()
A use-after-free in the Linux kernel Bluetooth ISO subsystem allows attackers to cause denial of service or potentially execute code via crafted Bluetooth connections.
- 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-2026-98459?
CVE-2026-98459 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: balance the parent hold in hci_bind_bis()
hci_conn_link() takes a lifetime reference to its parent with hci_conn_get(), but only takes an operational hold on the child. hci_conn_unlink() later balances both a hold and a reference on the parent.
The SCO and CIS paths pass a parent acquired from a connect helper, so it already has a hold. For an additional BIS, hci_bind_bis() obtains the parent from hci_conn_hash_lookup_big(), which returns a bare pointer. Unlinking the child then drops the parent's existing hold and can schedule it for disconnection while its socket is still using it.
Take a hold on the parent before linking it and drop that hold if linking fails. A successful link transfers the hold to hci_conn_unlink().
Which versions are affected by CVE-2026-98459?
How do I fix CVE-2026-98459?
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-2026-98459 being exploited?
There is no known exploitation of CVE-2026-98459 in the wild and no public exploit code.
Sources
Also known as AZL-109398, BELL-CVE-2026-98459, DEBIAN-CVE-2026-98459, GHSA-w8fc-m2x5-xcfp, UBUNTU-CVE-2026-98459.