CVE-2026-64160 in Linux
Summary
by MITRE • 07/19/2026
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix potential for tearing in ->remote_i_size and ->zero_point
Fix potential tearing in using ->remote_i_size and ->zero_point by copying i_size_read() and i_size_write() and using the same seqcount as for i_size.
We need to make sure that netfslib and the filesystems that use it always hold i_lock whilst updating any of the sizes to prevent i_size_seqcount from getting corrupted.
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Analysis
by VulDB Data Team • 07/19/2026
This vulnerability resides in the linux kernel's network filesystem subsystem, specifically addressing a race condition that could lead to data corruption during concurrent access scenarios. The issue manifests when multiple processes attempt to simultaneously modify file size information through the remote_i_size and zero_point attributes, creating potential for inconsistent or torn data states. The root cause stems from improper synchronization mechanisms when updating these critical file metadata fields, which are essential for maintaining filesystem consistency in distributed storage environments.
The technical flaw involves the absence of proper locking mechanisms around updates to i_size_read() and i_size_write() operations within the netfs library implementation. When filesystems utilizing the network filesystem subsystem perform concurrent modifications to file size attributes, they fail to consistently hold the i_lock during these critical sections, leading to potential corruption of the i_size_seqcount counter that tracks versioning information for size changes. This sequence count mechanism is crucial for maintaining data integrity and ensuring consistent reads across concurrent write operations.
The operational impact of this vulnerability extends beyond simple data inconsistency issues, potentially affecting the reliability of network filesystem operations in enterprise environments where concurrent access patterns are common. Systems utilizing network filesystems such as nfs, cifs, or other distributed storage protocols could experience file corruption, incomplete transfers, or inconsistent file size reporting when multiple processes attempt simultaneous updates to file metadata. This vulnerability particularly affects systems running kernel versions where the netfs subsystem is actively used for remote file operations, creating potential security implications through data integrity compromise.
Mitigation strategies must focus on ensuring consistent locking practices throughout the netfs library implementation and all filesystems that depend on it. The recommended approach involves enforcing mandatory acquisition of i_lock before any modifications to size-related attributes, aligning with established best practices for concurrent access control in kernel space. Security teams should prioritize kernel updates that implement proper seqcount handling and ensure that all network filesystem implementations consistently protect size modification operations through appropriate synchronization primitives. This vulnerability demonstrates the importance of maintaining strict consistency requirements in kernel-level file system operations, particularly when dealing with distributed storage environments where multiple clients may simultaneously access and modify the same files.
The vulnerability aligns with CWE-362 which addresses race conditions in concurrent programming scenarios, specifically highlighting the need for proper synchronization mechanisms in shared resource access. From an ATT&CK perspective, this represents a potential path for data integrity compromise that could be exploited by adversaries seeking to manipulate file system metadata or cause denial of service through corrupted file operations. The fix methodology emphasizes the critical importance of maintaining consistent locking patterns and sequence count management in kernel subsystems where concurrent access is expected, establishing a pattern that should be applied broadly across similar filesystem implementations to prevent analogous issues.