CVE-2026-45834
Description
A flaw was found in the Linux kernel's Bluetooth L2CAP (Logical Link Control and Adaptation Protocol) implementation. A missing null pointer guard in the l2cap_sock_state_change_cb() function can lead to a null pointer dereference. This vulnerability could allow an attacker to cause a system crash, resulting in a Denial of Service (DoS).
Statement
This Moderate impact flaw in the Linux kernel's Bluetooth L2CAP implementation can lead to a system crash due to a null pointer dereference. Exploitation requires local access or close proximity to a system with an active Bluetooth adapter, limiting the attack surface. Red Hat Enterprise Linux systems with Bluetooth enabled are affected.
Mitigation
To mitigate this issue, disable the Bluetooth functionality if it is not required. This can be achieved by blacklisting the `bluetooth` kernel module.
1. Create a new file `/etc/modprobe.d/disable-bluetooth.conf` with the following content:
`blacklist bluetooth`
2. Regenerate the initramfs:
`sudo dracut -f -v`
3. Reboot the system for the changes to take effect:
`sudo reboot`
Warning: Disabling the Bluetooth module will prevent all Bluetooth-related functionality on the system and requires a system reboot to take full effect.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.5 | 5.5 | N/A |
| Attack Vector | Local | Local | N/A |
| Attack Complexity | Low | Low | N/A |
| Privileges Required | Low | Low | N/A |
| User Interaction | None | None | N/A |
| Scope | Unchanged | Unchanged | N/A |
| Confidentiality | None | None | N/A |
| Integrity Impact | None | None | N/A |
| Availability Impact | High | High | N/A |
Vector
Red Hat: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Understanding the Weakness (CWE)
Availability
Technical Impact: DoS: Crash, Exit, or Restart
NULL pointer dereferences usually result in the failure of the process unless exception handling (on some platforms) is available and implemented. Even when exception handling is being used, it can still be very difficult to return the software to a safe state of operation.
Integrity,Confidentiality
Technical Impact: Execute Unauthorized Code or Commands; Read Memory; Modify Memory
In rare circumstances, when NULL is equivalent to the 0x0 memory address and privileged code can access it, then writing or reading memory is possible, which may lead to code execution.
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