CVE-2023-53838 in Linux
Summary
by MITRE • 12/09/2025
In the Linux kernel, the following vulnerability has been resolved:
f2fs: synchronize atomic write aborts
To fix a race condition between atomic write aborts, I use the inode lock and make COW inode to be re-usable thoroughout the whole atomic file inode lifetime.
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Analysis
by VulDB Data Team • 03/30/2026
The vulnerability identified as CVE-2023-53838 resides within the Linux kernel's f2fs (Flash-Friendly File System) implementation, specifically addressing a critical race condition that could lead to system instability and potential data corruption. This issue manifests during the handling of atomic write operations, where concurrent access patterns create scenarios that violate the expected behavior of file system transactions. The f2fs file system, designed primarily for flash storage devices such as ssd and embedded systems, implements atomic writes to ensure data integrity during critical operations. However, the race condition in question occurs when multiple processes attempt to abort atomic writes simultaneously, creating a scenario where the file system state becomes inconsistent and potentially corrupted.
The technical flaw stems from insufficient synchronization mechanisms during the atomic write abortion process within the f2fs implementation. Without proper locking mechanisms, concurrent threads can interfere with each other's operations, leading to a scenario where inode structures become corrupted or left in an inconsistent state. The race condition specifically affects the lifecycle management of copy-on-write (COW) inodes that are used during atomic write operations. When an atomic write is aborted, the system must ensure that the associated inode can be safely re-used for subsequent operations, but without adequate protection, the abort process can leave the inode in a state where it cannot be properly managed. This vulnerability falls under CWE-362, which describes race conditions in concurrent programming where multiple threads or processes access shared resources without proper synchronization.
The operational impact of this vulnerability extends beyond simple data corruption, potentially leading to system crashes, file system inconsistencies, and data loss in environments heavily reliant on f2fs. Systems using flash storage devices, embedded systems, and mobile devices that depend on f2fs for their file system operations are particularly at risk, as these platforms often experience high concurrency during write operations. The vulnerability can be exploited by malicious actors to cause denial of service conditions or potentially gain unauthorized access to system resources through file system manipulation. Attackers could leverage this race condition to create persistent inconsistencies in file system metadata, making it difficult for the system to recover from failures or maintain data integrity. This type of vulnerability aligns with ATT&CK technique T1490, which covers data destruction, as the race condition could result in permanent data corruption that requires system recovery or reboot to resolve.
The fix implemented addresses this vulnerability by introducing proper synchronization mechanisms through the use of inode locks, ensuring that atomic write abort operations are properly serialized. The solution requires that all COW inodes be made reusable throughout the entire atomic file inode lifetime, which prevents the race condition by ensuring exclusive access to inode resources during critical operations. This approach follows established best practices for concurrent programming and file system design, where proper locking mechanisms are essential to prevent data races. The fix essentially transforms the atomic write abortion process from a potentially unsafe concurrent operation into a controlled, serialized process that maintains file system integrity. By using inode locks, the system ensures that when an atomic write is aborted, the associated inode structure is properly cleaned up and made available for reuse without interference from concurrent operations, thereby eliminating the race condition that led to the vulnerability. The solution demonstrates proper adherence to file system consistency principles and provides a robust mechanism for handling concurrent atomic write operations in the f2fs implementation.