Threats Tagged 'cve-2026-64552'

A vulnerability in the Linux kernel's virtio-net driver was resolved involving an incorrect length check in the receive_big() function. The function's bounds check for device-announced packet length was too loose, allowing a malicious virtio backend to specify a length that causes an out-of-bounds write past the static fragment array. This results in a NULL fragment being passed up the receive path, potentially leading to memory corruption. The issue was fixed by tightening the length bounds to match the actual buffer size advertised by add_recvbuf_big().

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.