CVE-2026-31663

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

xfrm: hold dev ref until after transport_finish NF_HOOK

After async crypto completes, xfrm_input_resume() calls dev_put()

immediately on re-entry before the skb reaches transport_finish.

The skb->dev pointer is then used inside NF_HOOK and its okfn,

which can race with device teardown.

Remove the dev_put from the async resumption entry and instead

drop the reference after the NF_HOOK call in transport_finish,

using a saved device pointer since NF_HOOK may consume the skb.

This covers NF_DROP, NF_QUEUE and NF_STOLEN paths that skip

the okfn.

For non-transport exits (decaps, gro, drop) and secondary

async return points, release the reference inline when

async is set.