CVE-2022-49996 in Linux
Summary
by MITRE • 06/18/2025
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix possible memory leak in btrfs_get_dev_args_from_path()
In btrfs_get_dev_args_from_path(), btrfs_get_bdev_and_sb() can fail if the path is invalid. In this case, btrfs_get_dev_args_from_path() returns directly without freeing args->uuid and args->fsid allocated before, which causes memory leak.
To fix these possible leaks, when btrfs_get_bdev_and_sb() fails, btrfs_put_dev_args_from_path() is called to clean up the memory.
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Analysis
by VulDB Data Team • 11/30/2025
The vulnerability identified as CVE-2022-49996 represents a memory leak condition within the Linux kernel's btrfs file system implementation that stems from inadequate error handling during device argument processing. This flaw manifests in the btrfs_get_dev_args_from_path() function where the system attempts to retrieve device arguments from a specified path while simultaneously calling btrfs_get_bdev_and_sb() to obtain block device information and superblock data. When btrfs_get_bdev_and_sb() encounters an invalid path or other failure conditions, it returns an error status that should trigger proper cleanup procedures but instead allows the function to exit prematurely without releasing previously allocated memory resources.
The technical nature of this vulnerability aligns with CWE-401, which specifically addresses memory leaks in software systems where allocated memory is not properly freed following error conditions. The flaw occurs because the btrfs_get_dev_args_from_path() function allocates memory for args->uuid and args->fsid variables before calling btrfs_get_bdev_and_sb(), but fails to implement proper cleanup logic when the subsequent call returns an error. This creates a scenario where memory allocated for device identification parameters remains in the system's memory space indefinitely, potentially leading to progressive memory consumption over time. The vulnerability demonstrates a classic improper cleanup pattern where error paths in function execution do not properly handle resource deallocation, a common weakness in systems programming that can be exploited to degrade system performance or availability.
From an operational impact perspective, this memory leak vulnerability can contribute to system resource exhaustion, particularly on systems running btrfs file systems with high I/O activity or those that frequently attempt to access invalid paths. The cumulative effect of multiple memory leaks can lead to reduced system performance, increased memory pressure, and potentially system instability or crashes. While the individual memory leak may appear minor, in environments with intensive file system operations or automated scripts that repeatedly attempt to access invalid paths, the accumulation of leaked memory can become significant. The vulnerability affects systems using the btrfs file system implementation within the Linux kernel, particularly those that rely on device argument processing for file system operations, backup procedures, or system maintenance tasks that involve path validation.
The mitigation strategy for this vulnerability involves applying the kernel patch that implements proper error handling by calling btrfs_put_dev_args_from_path() whenever btrfs_get_bdev_and_sb() fails. This remediation follows established security practices for memory management in kernel space code and aligns with the ATT&CK technique T1490, which addresses the exploitation of resource consumption vulnerabilities through memory leaks. System administrators should prioritize applying the relevant kernel updates from their distribution vendors to ensure the patched version is deployed across all affected systems. The fix demonstrates the importance of proper resource management in kernel code and reinforces the principle that error paths in system-level functions must always include complete cleanup procedures to prevent resource leakage. Organizations maintaining btrfs file systems should monitor their system memory usage patterns to detect potential impacts from this vulnerability and ensure comprehensive patch management processes are in place to address similar memory management issues in other kernel subsystems.