CVE-2026-72365
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix writethrough to use collection offload
Fix writethrough write to set NETFS_RREQ_OFFLOAD_COLLECTION on the request so that collection is processed asynchronously rather than only right at the end - and also so that asynchronous O_SYNC writes get collected at all.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability addressed in this linux kernel patch relates to improper handling of write operations within the network filesystem subsystem, specifically affecting how data is processed during writethrough operations. This issue impacts the netfs framework which manages network filesystems and their interaction with local storage systems. The flaw occurs when the kernel attempts to process write requests that should be handled through asynchronous collection mechanisms rather than synchronous processing at the final stage of operation.
The technical implementation problem stems from the incorrect flag usage during writethrough write operations where the NETFS_RREQ_OFFLOAD_COLLECTION flag was not being properly set on requests. This omission caused the system to process all collection activities synchronously at the end of operations rather than allowing asynchronous processing throughout the write cycle. The patch specifically addresses this by ensuring that when writethrough writes occur, the NETFS_RREQ_OFFLOAD_COLLECTION flag is correctly applied to request structures, enabling proper asynchronous handling.
This vulnerability has significant operational implications for network filesystem performance and reliability, particularly in environments where asynchronous I/O operations are critical for maintaining system responsiveness. Without proper offload collection mechanisms, write operations may experience increased latency and reduced throughput as the system cannot efficiently process multiple concurrent requests. The impact extends to applications that rely heavily on network filesystems for data storage and retrieval, potentially causing performance bottlenecks during high-volume write operations.
The mitigation implemented through this patch aligns with established security practices by ensuring proper request handling within kernel subsystems and follows principles outlined in the common weakness enumeration framework where improper handling of asynchronous operations can lead to performance degradation and potential denial-of-service conditions. This fix also corresponds to techniques described in attack patterns related to kernel-level resource management issues, where incorrect flag settings can create opportunities for system instability or performance degradation. The solution ensures that network filesystem operations maintain proper separation between synchronous and asynchronous processing paths, preventing the accumulation of pending requests that could otherwise block system resources.
From a security perspective, this vulnerability represents a potential denial-of-service vector where improper write handling could cause system resource exhaustion during high-volume network filesystem operations. The fix ensures that asynchronous O_SYNC writes can be properly collected and processed without blocking the main execution path, which maintains system stability under concurrent load conditions. This type of kernel-level improvement is essential for maintaining robust network filesystem performance in enterprise environments where reliable data access is critical.