CVE-2022-49831 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
btrfs: zoned: initialize device's zone info for seeding
When performing seeding on a zoned filesystem it is necessary to initialize each zoned device's btrfs_zoned_device_info structure, otherwise mounting the filesystem will cause a NULL pointer dereference.
This was uncovered by fstests' testcase btrfs/163.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 11/10/2025
The vulnerability described in CVE-2022-49831 represents a critical null pointer dereference issue within the Linux kernel's btrfs filesystem implementation, specifically affecting zoned storage devices. This flaw manifests during the seeding process of zoned filesystems where the btrfs_zoned_device_info structure fails to be properly initialized for each zoned device involved in the operation. The issue was identified through comprehensive testing by the fstests framework, specifically through testcase btrfs/163, which exposed the underlying memory management failure in the kernel's handling of zoned storage environments.
The technical root cause of this vulnerability stems from inadequate initialization of device-specific metadata structures within the btrfs filesystem driver. When a zoned filesystem undergoes the seeding operation, the kernel must properly establish zone information for each storage device in the array. However, the implementation fails to initialize the btrfs_zoned_device_info structure, leaving critical pointers uninitialized and pointing to NULL values. This initialization gap becomes problematic when the filesystem attempts to mount, as subsequent operations reference these uninitialized structures, leading to immediate system crashes through null pointer dereference exceptions.
The operational impact of this vulnerability extends beyond simple system instability, as it affects the reliability of storage operations on zoned devices such as those used in modern enterprise storage arrays and NVMe devices. When a system attempts to mount a zoned btrfs filesystem that has undergone seeding operations, the kernel's memory management subsystem encounters a null pointer dereference, resulting in immediate system termination or kernel panic. This represents a severe denial of service condition that can compromise data integrity and availability in storage environments where zoned filesystems are utilized, particularly in high-performance computing and data center environments where such storage configurations are increasingly common.
The vulnerability aligns with CWE-476, which addresses null pointer dereference conditions in software implementations. From an attack perspective, this issue can be leveraged to cause system instability and denial of service conditions, potentially affecting system availability in production environments. The ATT&CK framework categorizes this as a system compromise technique through kernel-level exploitation, where adversaries could potentially trigger the null pointer dereference by initiating specific filesystem operations on zoned storage devices. The fix implemented in the kernel ensures proper initialization of the btrfs_zoned_device_info structure during seeding operations, preventing the subsequent NULL pointer dereference during mount operations.
This vulnerability highlights the importance of proper resource initialization in kernel-space implementations, particularly when dealing with complex storage subsystems that require extensive metadata management. The fix demonstrates the necessity of comprehensive testing procedures for storage subsystems, as the issue was only uncovered through specific test cases within the fstests framework. Organizations utilizing zoned storage environments should prioritize applying the kernel updates that contain this fix to prevent potential system crashes and maintain the reliability of their storage infrastructure. The vulnerability serves as a reminder of the critical nature of proper initialization sequences in kernel drivers and the potential for seemingly minor initialization failures to result in catastrophic system failures.