CVE-2026-23395 Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ

High 8.8 Published 25 Mar 2026 Updated 19 Oct 2026

A flaw in the Linux kernel Bluetooth L2CAP module allows remote attackers to cause a denial of service via multiple connection requests with the same identifier.

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-2026-23395?

CVE-2026-23395 is a high-severity vulnerability in Linux kernel, published on 25 Mar 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 accepting multiple L2CAP_ECRED_CONN_REQ

Currently the code attempts to accept requests regardless of the command identifier which may cause multiple requests to be marked as pending (FLAG_DEFER_SETUP) which can cause more than L2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer causing an overflow.

The spec is quite clear that the same identifier shall not be used on subsequent requests:

'Within each signaling channel a different Identifier shall be used for each successive request or indication.' https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d

So this attempts to check if there are any channels pending with the same identifier and rejects if any are found.

Weakness: CWE-20

Which versions are affected by CVE-2026-23395?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-23395?

Apply the vendor's patch.

Is CVE-2026-23395 being exploited?

There is no known exploitation of CVE-2026-23395 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as AZL-80705, BELL-CVE-2026-23395, DEBIAN-CVE-2026-23395, GHSA-5r99-pj6c-hg6v, ROOT-OS-DEBIAN-11-CVE-2026-23395, ROOT-OS-DEBIAN-12-CVE-2026-23395 and 4 more.