CVE-2025-38273

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

net: tipc: fix refcount warning in tipcaeadencrypt

syzbot reported a refcount warning [1] caused by calling get_net() on a network namespace that is being destroyed (refcount=0). This happens when a TIPC discovery timer fires during network namespace cleanup.

The recently added getnet() call in commit e279024617134 ("net/tipc: fix slab-use-after-free Read in tipcaeadencryptdone") attempts to hold a reference to the network namespace. However, if the namespace is already being destroyed, its refcount might be zero, leading to the use-after-free warning.

Replace getnet() with maybeget_net(), which safely checks if the refcount is non-zero before incrementing it. If the namespace is being destroyed, return -ENODEV early, after releasing the bearer reference.