CVE-2022-48626 in Linux
Summary
by MITRE • 02/26/2024
In the Linux kernel, the following vulnerability has been resolved:
moxart: fix potential use-after-free on remove path
It was reported that the mmc host structure could be accessed after it was freed in moxart_remove(), so fix this by saving the base register of the device and using it instead of the pointer dereference.
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Analysis
by VulDB Data Team • 08/27/2024
The vulnerability identified as CVE-2022-48626 represents a critical use-after-free condition within the Linux kernel's mmc (MultiMediaCard) subsystem, specifically affecting the moxart driver implementation. This flaw resides in the device removal path where the kernel's memory management logic fails to properly handle the lifecycle of hardware abstraction structures. The issue manifests when the moxart_remove() function attempts to access an mmc host structure that has already been freed from memory, creating a scenario where subsequent operations may dereference invalid memory pointers. Such memory corruption vulnerabilities are particularly dangerous as they can lead to arbitrary code execution or system crashes, especially when exploited in kernel space contexts where privilege levels are highest.
The technical root cause of this vulnerability stems from improper memory management during device teardown operations within the moxart driver. When the remove function executes, it attempts to access device registers through a pointer that has already been freed, violating fundamental memory safety principles. This pattern aligns with CWE-416, which describes use-after-free vulnerabilities where program memory is accessed after it has been freed, and represents a classic example of improper resource management in kernel code. The vulnerability specifically impacts the mmc host structure which serves as the abstraction layer between the hardware device and the kernel's storage subsystem, making it a critical component for secure device operation.
The operational impact of this vulnerability extends beyond simple system instability to encompass potential security compromise of embedded systems utilizing the moxart mmc controller. Attackers could potentially exploit this condition to execute arbitrary code with kernel privileges, effectively bypassing system security boundaries and gaining complete control over affected devices. Systems running Linux kernels with the affected moxart driver implementation are particularly vulnerable, especially those deployed in embedded environments where kernel updates may be infrequent or restricted. The vulnerability's exploitation potential is heightened by the fact that it occurs during normal device removal operations, making it difficult to detect and prevent through standard runtime monitoring mechanisms.
Mitigation strategies for CVE-2022-48626 require immediate kernel updates addressing the specific memory management flaw in the moxart driver. System administrators should prioritize patching affected kernel versions to prevent exploitation, as the vulnerability directly impacts kernel memory safety. The fix implemented addresses the issue by preserving the base register address of the device before freeing the associated memory structure, then utilizing this saved register reference instead of pointer dereferencing during cleanup operations. This approach follows established security practices for preventing use-after-free conditions by ensuring proper resource lifecycle management and aligns with ATT&CK technique T1068 which covers local privilege escalation through kernel vulnerabilities. Organizations should also implement comprehensive kernel security monitoring to detect potential exploitation attempts and maintain updated security policies for embedded system management.