CVE-2026-23066

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

rxrpc: Fix recvmsg() unconditional requeue

If rxrpc_recvmsg() fails because MSG_DONTWAIT was specified but the call at

the front of the recvmsg queue already has its mutex locked, it requeues

the call - whether or not the call is already queued. The call may be on

the queue because MSG_PEEK was also passed and so the call was not dequeued

or because the I/O thread requeued it.

The unconditional requeue may then corrupt the recvmsg queue, leading to

things like UAFs or refcount underruns.

Fix this by only requeuing the call if it isn't already on the queue - and

moving it to the front if it is already queued. If we don't queue it, we

have to put the ref we obtained by dequeuing it.

Also, MSG_PEEK doesn't dequeue the call so shouldn't call

rxrpc_notify_socket() for the call if we didn't use up all the data on the

queue, so fix that also.