CVE-2026-72372 in Linux
Summary
by MITRE • 08/15/2026
In the Linux kernel, the following vulnerability has been resolved:
afs: Fix lack of locking around modifications of net->cells_dyn_ino
Fix the lack of locking around modifications of net->cells_dyn_ino by taking net->cells_lock exclusively. This also requires to cell to be removed from net->cells_dyn_ino in afs_destroy_cell_work() rather than in afs_cell_destroy() as the latter runs in RCU cleanup context and sleeping locks cannot be taken there.
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Analysis
by VulDB Data Team • 08/15/2026
The vulnerability identified in the Linux kernel pertains to improper synchronization mechanisms within the Andrew File System implementation, specifically concerning dynamic inode management for cell structures. This flaw exists in the afs subsystem which handles network file system operations and represents a critical concurrency issue that could lead to system instability and potential security implications.
The technical root cause involves insufficient locking around modifications to the net->cells_dyn_ino data structure, which tracks dynamically allocated inodes for AFS cells within the network namespace. Without proper exclusive locking mechanisms, concurrent access patterns during cell creation and destruction operations can result in race conditions where multiple threads attempt to modify shared data structures simultaneously, potentially leading to memory corruption or inconsistent state management.
This vulnerability directly relates to CWE-362, which identifies concurrent execution issues such as race conditions that can occur when multiple threads or processes access shared resources without proper synchronization. The flaw manifests when the afs_destroy_cell_work function attempts to remove cells from the dynamic inode list, but operates in an RCU (Read-Copy-Update) cleanup context where sleeping locks cannot be acquired, creating a fundamental mismatch between the locking requirements and execution context.
The operational impact of this vulnerability extends beyond simple system instability, as it can enable malicious actors to potentially exploit race conditions for privilege escalation or denial-of-service attacks against systems running AFS services. Network file servers utilizing AFS may experience crashes or data inconsistencies when multiple concurrent operations occur during cell management phases, particularly under high load conditions with frequent cell creation and destruction cycles.
Mitigation strategies should focus on implementing proper locking mechanisms using the existing net->cells_lock exclusive lock as specified in the patch. System administrators should ensure immediate deployment of kernel updates containing this fix, while also monitoring for any anomalous behavior in AFS services that might indicate exploitation attempts. The solution addresses the fundamental architectural issue by repositioning cell removal operations to occur in appropriate contexts where locking is permissible, thereby maintaining data structure integrity during concurrent operations and preventing potential security implications associated with memory corruption vulnerabilities.
The fix demonstrates proper adherence to kernel development practices for concurrent access control and follows established patterns for managing RCU cleanup contexts while maintaining necessary synchronization guarantees. This represents a complete solution addressing both the immediate locking deficiency and the contextual constraint that prevented proper lock acquisition during cell destruction operations, thereby eliminating the race condition that could have been exploited by malicious actors.