CVE-2026-45836
Description
A flaw was found in the Linux kernel's Bluetooth L2CAP subsystem. This vulnerability, a null-pointer dereference, occurs due to a missing NULL guard in the l2cap_sock_get_sndtimeo_cb() function. A local attacker could exploit this flaw to trigger a system crash, leading to a Denial of Service (DoS).
Statement
This Moderate flaw in the Linux kernel's Bluetooth L2CAP subsystem allows a local attacker to trigger a null-pointer dereference, leading to a system crash and Denial of Service. Exploitation requires local access to the system, limiting the attack vector compared to remote vulnerabilities.
Mitigation
To mitigate this issue, if Bluetooth functionality is not required, the `bluetooth` kernel module can be prevented from loading. This can be achieved by creating a modprobe configuration file.
Create a file named `/etc/modprobe.d/disable-bluetooth.conf` with the following content:
`install bluetooth /bin/true`
`blacklist bluetooth`
After creating the file, regenerate the initramfs and reboot the system for the changes to take effect.
`dracut -f -v`
`reboot`
Disabling the `bluetooth` module will prevent all Bluetooth-related functionality on the system.
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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