CVE-2026-63975 Bluetooth: L2CAP: Fix possible crash on l2cap_ecred_conn_rsp
A use-after-free vulnerability in the Linux kernel Bluetooth L2CAP module allows attackers to cause a system crash via crafted connection responses.
- 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-2026-63975?
CVE-2026-63975 is a high-severity use after free vulnerability in Linux kernel, published on 19 Jul 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: Fix possible crash on l2cap_ecred_conn_rsp
If dcid is received for an already-assigned destination CID the spec requires that both channels to be discarded, but calling l2cap_chan_del may invalidate the tmp cursor created by list_for_each_entry_safe and in fact it is the wrong procedure as the chan->dcid may be assigned previously it really needs to be disconnected.
Calling l2cap_chan_clone directly may still lead to l2cap_chan_del so instead schedule l2cap_chan_timeout with delay 0 to close the channel asynchronously.
Which versions are affected by CVE-2026-63975?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2026-63975?
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-2026-63975 being exploited?
There is no known exploitation of CVE-2026-63975 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2026-63975, DEBIAN-CVE-2026-63975, GHSA-g36p-q7h2-h3pp, ROOT-OS-UBUNTU-2204-CVE-2026-63975, UBUNTU-CVE-2026-63975.