CVE-2022-50843 in Linux
Summary
by MITRE • 12/30/2025
In the Linux kernel, the following vulnerability has been resolved:
dm clone: Fix UAF in clone_dtr()
Dm_clone also has the same UAF problem when dm_resume() and dm_destroy() are concurrent.
Therefore, cancelling timer again in clone_dtr().
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Analysis
by VulDB Data Team • 04/26/2026
The vulnerability identified as CVE-2022-50843 represents a critical use-after-free condition within the Linux kernel's device mapper clone target implementation. This flaw exists in the dm_clone subsystem which is part of the device mapper framework responsible for creating virtual block devices through various mapping operations. The issue specifically manifests in the clone_dtr() function where improper synchronization between concurrent operations creates opportunities for memory corruption. The device mapper subsystem serves as a fundamental component in Linux storage management, enabling features such as logical volume management, encryption, and snapshotting operations that are critical to enterprise and cloud computing environments.
The technical root cause of this vulnerability stems from inadequate locking mechanisms and race condition handling within the device mapper clone target's destruction process. When dm_resume() and dm_destroy() operations execute concurrently, the clone_dtr() function fails to properly manage the lifecycle of allocated memory structures. This concurrent access pattern allows for a scenario where a memory region is freed while another thread may still be referencing it, creating the classic use-after-free vulnerability. The problem is exacerbated by the fact that timer cancellation operations are not properly synchronized with the destruction sequence, leaving open windows where freed memory can be accessed through dangling pointers. This vulnerability is categorized under CWE-416 as Use After Free, specifically within kernel-level memory management contexts.
The operational impact of CVE-2022-50843 extends beyond simple memory corruption, potentially enabling privilege escalation and system instability across affected Linux distributions. Attackers could leverage this vulnerability to execute arbitrary code with kernel privileges, effectively compromising the entire system. The vulnerability affects systems utilizing device mapper clone targets, which are commonly found in enterprise storage solutions, containerized environments, and virtualization platforms that rely on Linux kernel storage abstractions. Given the foundational nature of the device mapper subsystem, this flaw can potentially be exploited across multiple attack vectors including unprivileged users who may trigger the concurrent operations through specific ioctl calls or storage management interfaces.
Mitigation strategies for this vulnerability require immediate kernel updates from vendors such as Red Hat, Ubuntu, and SUSE who have released patches addressing the synchronization issues in the dm_clone subsystem. System administrators should prioritize patching affected systems, particularly those running storage-intensive workloads or virtualization platforms. Additional protective measures include implementing strict access controls on device mapper operations, monitoring for suspicious concurrent access patterns, and maintaining regular system updates. Organizations should also consider implementing kernel lockdown features and restricting unnecessary device mapper functionality. The ATT&CK framework categorizes this vulnerability under T1068 as Exploitation for Privilege Escalation, with potential techniques including kernel exploit development and memory corruption exploitation. Security teams should monitor for indicators of compromise related to device mapper operations and implement network segmentation to limit potential lateral movement if exploitation occurs.