Race Condition in Linux Kernel's FUSE Module Impacting Concurrent Queue Access

CVE-2026-80858

What is CVE-2026-80858?

A race condition exists in the Linux kernel's FUSE module, specifically within the io-uring queues. The issue arises during the initialization of a fuse_ring_queue when the queue's pointer is published without ensuring proper ordering of initialization. The use of WRITE_ONCE() does not enforce the necessary sequencing of field initialization, which can lead to undefined behavior when multiple readers concurrently access the pointer. To mitigate this, the queue should be published with smp_store_release(), ensuring that the necessary initializations occur before the reader accesses the queue pointer. Developers and system administrators should ensure that systems are kept up to date to prevent potential exploitation of this vulnerability.

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