CVE-2026-64552

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

virtio-net: fix len check in receive_big()

receive_big() bounds the device-announced length by

(big_packets_num_skbfrags + 1) * PAGE_SIZE. That is still too loose:

add_recvbuf_big() sets sg[1] to start at offset

sizeof(struct padded_vnet_hdr) into the first page, so the chain

actually carries hdr_len + (PAGE_SIZE - sizeof(padded_vnet_hdr)) +

big_packets_num_skbfrags * PAGE_SIZE bytes -- 20 bytes less than the

check allows for the common hdr_len == 12 case.

A malicious virtio backend can announce a len in that gap. page_to_skb()

then walks one frag past the page chain, storing a NULL page->private

into skb_shinfo()->frags[MAX_SKB_FRAGS], which is both an out-of-bounds

write past the static frag array and a NULL frag handed up the rx path.

Bound len by the size add_recvbuf_big() actually advertised.