CVE-2026-43134: Bluetooth: L2CAP: Fix missing key size check for L2CAP_LE_CONN_REQ
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix missing key size check for L2CAPLECONNREQ
This adds a check for encryption key size upon receiving L2CAPLECONNREQ which is required by L2CAP/LE/CFC/BV-15-C which expects L2CAPCRLEBADKEYSIZE.
Affected Software
Event History
Frequently Asked Questions
What access does an attacker need to exploit this issue?
The CVSS vector indicates adjacent-network attack access with no privileges or user interaction required. In practice, the attacker would need to be within Bluetooth communication range of the affected system.
What security impact is indicated?
The CVSS score is 8.1 (High) and indicates high confidentiality and integrity impact, with no availability impact. The flaw concerns handling an L2CAP_LE_CONN_REQ when the encryption key size is insufficient.
How can I identify systems that need remediation?
Identify Linux systems with Bluetooth enabled that use L2CAP over Bluetooth Low Energy. The supplied information does not list affected or fixed kernel version numbers; use the referenced stable-kernel commits to determine whether the fix is present in the deployed kernel source or vendor package.
What should be done if an update cannot be applied immediately?
The provided data does not specify a workaround. Reducing Bluetooth exposure, such as disabling Bluetooth where it is not required, can limit adjacent attackers' ability to reach the vulnerable L2CAP/LE handling path.