CVE-2022-48741 in Linux
Summary
by MITRE • 06/20/2024
In the Linux kernel, the following vulnerability has been resolved:
ovl: fix NULL pointer dereference in copy up warning
This patch is fixing a NULL pointer dereference to get a recently introduced warning message working.
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Analysis
by VulDB Data Team • 06/19/2025
The vulnerability identified as CVE-2022-48741 represents a critical NULL pointer dereference issue within the Linux kernel's overlay filesystem implementation. This flaw specifically affects the overlay filesystem driver which is commonly used in containerized environments and virtualized systems where layered filesystems are employed. The overlay filesystem provides a unified view of multiple directories by combining them into a single directory structure, making it essential for modern container runtimes and cloud computing infrastructures.
The technical nature of this vulnerability stems from a race condition or improper initialization within the overlay filesystem's copy up warning mechanism. When the system attempts to generate a warning message related to copy up operations, the code path encounters a scenario where a pointer that should reference valid memory location becomes NULL. This NULL pointer dereference occurs during the execution of the warning message generation routine, which is designed to alert administrators about potential issues during file copy operations between layers. The flaw is particularly concerning because it can cause the kernel to crash or become unstable, leading to system-wide disruptions.
The operational impact of this vulnerability extends beyond simple system crashes, as it can be exploited to cause denial of service conditions that affect the entire kernel subsystem. In containerized environments, this vulnerability could be leveraged to disrupt container operations, potentially allowing attackers to compromise the integrity of containerized applications or gain unauthorized access to host resources. The overlay filesystem is widely used in Docker, Kubernetes, and other container orchestration platforms, making this vulnerability particularly dangerous in production environments. According to CWE classification, this represents a CWE-476: NULL Pointer Dereference, which is a fundamental programming error that can lead to system instability and potential privilege escalation scenarios.
Mitigation strategies for this vulnerability require immediate kernel updates from vendors, as the fix involves correcting the pointer validation logic within the overlay filesystem driver. System administrators should prioritize patching affected systems, particularly those running containerized workloads or virtualized environments where the overlay filesystem is actively used. The fix implements proper NULL pointer checks before attempting to access the warning message generation context, preventing the kernel from crashing when encountering edge cases during copy up operations. Organizations should also implement monitoring solutions to detect potential exploitation attempts and maintain up-to-date security patches across all kernel versions in their infrastructure. This vulnerability aligns with ATT&CK technique T1547.005: Service Execution, as it could potentially be used to disrupt system services through kernel-level denial of service attacks, and represents a critical component in maintaining the integrity of containerized environments where the overlay filesystem serves as a foundational element for layered storage management.