CVE-2026-98107 Bluetooth: L2CAP: fix out-of-bounds write in l2cap_ecred_connect
An out-of-bounds write in the Linux kernel Bluetooth L2CAP module allows attackers to cause memory corruption, potentially leading to code execution or system crashes.
- 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-2026-98107?
CVE-2026-98107 is a memory corruption vulnerability in Linux, published on 25 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: fix out-of-bounds write in l2cap_ecred_connect
l2cap_chan_connect() tries to ensure there are no more than L2CAP_ECRED_CONN_SCID_MAX pending ECRED channels, so they fit in the same L2CAP_ECRED_CONN_REQ that l2cap_ecred_connect() constructs.
However, the check only counts deferred channels. If 6 L2CAP sockets are connected at the same time in order DDDDND (D=deferred, N=non-deferred), the last can bump the total to max+1. It results to one __le16 written out of bounds of the scid array, and an invalid ECRED_CONN_REQ being sent.
Fix by leaving room for the non-deferred pending ECRED channels in the counting in l2cap_chan_connect(), so the limit can't be exceeded.
Move counting under same critical section where the channel is added. Although race conditions involving this appear unreachable, it's easier to see.
Also add WARN_ON_ONCE check in l2cap_ecred_defer_connect() to make this less brittle.
Which versions are affected by CVE-2026-98107?
How do I fix CVE-2026-98107?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-98107 being exploited?
There is no known exploitation of CVE-2026-98107 in the wild and no public exploit code.
Sources
Also known as AZL-104804, BELL-CVE-2026-98107, DEBIAN-CVE-2026-98107, GHSA-vgxx-7qq2-4hrv, UBUNTU-CVE-2026-98107.