CVE-2026-80858

In the Linux kernel, the following vulnerability has been resolved:

fuse: publish io-uring queues with release semantics

fuseuringcreatequeue() initializes a fuseringqueue and then publishes the pointer into ring->queues[qid] with WRITEONCE() under the fch->lock. There are several readers that may concurrently be fetching that pointer locklessly and then deferencing it.

WRITEONCE() doesn't ensure ordering of the queue's field initialization before the ring->queues[qid] pointer assignment. The queue must be published with smpstore_release() so the field initialization is guaranteed to happen before.

Readers in paths where the read may happen concurrently with the store need to use READ_ONCE() because any race involving a plain access is undefined.