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

xfrm: account XFRMA_IF_ID in aevent size calculation

xfrm_get_ae() allocates the reply skb with xfrm_aevent_msgsize(), then
build_aevent() appends attributes including XFRMA_IF_ID when x->if_id is
set.

xfrm_aevent_msgsize() does not include space for XFRMA_IF_ID. For states
with if_id, build_aevent() can fail with -EMSGSIZE and hit BUG_ON(err < 0)
in xfrm_get_ae(), turning a malformed netlink interaction into a kernel
panic.

Account XFRMA_IF_ID in the size calculation unconditionally and replace
the BUG_ON with normal error unwinding.