Bluetooth cmtp File Refcount Vulnerability in Linux Kernel
Summary
GSD-2021-1000691: Bluetooth: cmtp: fix file refcount when cmtp_attach_device fails. Affects Kernel versions < 77c559407276ed4a8854dafc4a5efc8608e51906. No fix is published. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
The Linux Kernel is a widely used open-source operating system kernel that serves as the foundation for various Linux distributions. It provides essential functionality for the system, including device drivers, memory management, and process scheduling. The Bluetooth subsystem in the Linux Kernel enables communication between devices using Bluetooth technology. The cmtp (Connection Manager Transport Protocol) module is responsible for managing file transfers over Bluetooth connections.
Vulnerability Detail
The Bluetooth cmtp module in the Linux Kernel is vulnerable to a file refcount issue when the cmtp_attach_device function fails. This vulnerability can be exploited by an attacker to cause a denial-of-service condition or potentially execute arbitrary code with kernel privileges. When cmtp_attach_device fails, it fails to properly handle the file refcount, leading to a use-after-free vulnerability. An attacker can trigger this vulnerability by sending specially crafted Bluetooth packets to a vulnerable system.
How To Fix
No fixed version is published for this vulnerability.
Tip — Not sure whether your app is affected? Vulert can check the versions your app actually runs. Scan free →
Workaround
As a temporary workaround, users can disable the cmtp module by blacklisting it. This can be achieved by adding the following line to the /etc/modprobe.d/blacklist.conf file:
blacklist cmtp
Conclusion
The Bluetooth cmtp file refcount vulnerability in the Linux Kernel can be exploited to cause a denial-of-service condition or potentially execute arbitrary code with kernel privileges. It is crucial to update the Linux Kernel to version v4.9.271 or later to mitigate this vulnerability. Additionally, users can temporarily disable the cmtp module through blacklisting. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for Kernel →
FAQ
This vulnerability can lead to a denial-of-service condition or potential arbitrary code execution with kernel privileges.
An attacker can exploit this vulnerability by sending specially crafted Bluetooth packets to a vulnerable system.
Yes, the vulnerability is fixed in Linux Kernel version v4.9.271 by commit 77c559407276ed4a8854dafc4a5efc8608e51906.
The vulnerability was introduced in an unknown version and is fixed in Linux Kernel version v4.9.271. It is recommended to update to the latest version to ensure the fix is applied.
Yes, users can mitigate this vulnerability by disabling the cmtp module through blacklisting.
Related vulnerabilities
Recent vulnerabilities recorded for Kernel.
