CVE-2021-33034: Linux Kernel Bluetooth Subsystem Use-After-Free Vulnerability
Summary
CVE-2021-33034: In hci_send_acl and related functions of hci_core.c, there is a possible way to corrupt memory due to a use after free. Affects :linux_kernel: versions >= :0, < :2022-06-05. Fixed in :2022-06-05. How to fix ↓
Also tracked for
- linux · Debian:11
The same CVE-2021-33034 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
The Linux Kernel is a core component of the Android operating system, managing hardware resources and providing essential services to applications. The Bluetooth subsystem within the kernel facilitates wireless communication between devices. This subsystem is critical for enabling features such as file transfers, audio streaming, and device pairing. However, it is susceptible to vulnerabilities that can lead to severe security risks, including privilege escalation.
Vulnerability Detail
The vulnerability identified as CVE-2021-33034 is a use-after-free issue in the hci_send_acl function within the Bluetooth subsystem of the Linux Kernel. This flaw allows an attacker to exploit memory corruption, potentially leading to local escalation of privileges. The vulnerability arises when memory is freed but still accessed, which can result in unpredictable behavior or system crashes. Exploitation does not require user interaction, making it particularly dangerous.
How To Fix
Minimum fixed version
:2022-06-05
This is the first release that contains the fix.
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Workaround
As a temporary measure, users can disable Bluetooth functionality on their devices until the kernel is updated. This can be done through the device settings or by using the command line to turn off the Bluetooth service.
Conclusion
CVE-2021-33034 is a significant vulnerability in the Linux Kernel's Bluetooth subsystem that poses a risk of privilege escalation. Users are strongly encouraged to apply the necessary updates to mitigate this risk. Additionally, using tools like Vulert can help in monitoring for such vulnerabilities in real-time.
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FAQ
CVE-2021-33034 is a vulnerability in the Linux Kernel's Bluetooth subsystem that allows for memory corruption due to a use-after-free error.
An attacker can exploit this vulnerability to escalate privileges on the system without requiring user interaction.
Exploitation of this vulnerability can lead to unauthorized access to system resources and potentially compromise the entire system.
Yes, a patch is available and users are advised to update their Linux Kernel to the version released on or after June 5, 2022.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit the Vulert playground at Vulert Scanner to check if your application is affected without needing to sign up.
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