CVE-2026-90093 Bluetooth: L2CAP: access chan->conn safely in get/setsockopt
A use-after-free vulnerability in the Linux kernel Bluetooth L2CAP module allows attackers to cause a system crash via crafted socket operations.
- 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-2026-90093?
CVE-2026-90093 is a high-severity use after free vulnerability in Linux, published on 17 Sep 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: L2CAP: access chan->conn safely in get/setsockopt
Since commit b66774b48dd9 ("Bluetooth: L2CAP: Fix UAF in channel timeout by holding conn ref") l2cap_chan::conn has held reference and remains non-NULL also after the corresponding hci_conn is deleted. In this state accessing various fields eg. hci_conn::hdev is invalid, which leads to KASAN crash in l2cap_sock_setsockopt() access of conn->hcon->hdev.
Check l2cap_chan::conn.hcon corresponds to an alive hci_conn before trying to use it in l2cap_sock.c. Hold l2cap_chan_lock() in getsockopt/setsockopt to ensure it stays alive, and to avoid data races in l2cap_chan fields.
Which versions are affected by CVE-2026-90093?
How do I fix CVE-2026-90093?
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-2026-90093 being exploited?
There is no known exploitation of CVE-2026-90093 in the wild and no public exploit code.
Sources
Also known as AZL-102689, BELL-CVE-2026-90093, DEBIAN-CVE-2026-90093, GHSA-vcch-q6jx-pg5j, UBUNTU-CVE-2026-90093.