CVE-2026-64552 virtio-net: fix len check in receive_big()
A malicious virtio backend can trigger an out-of-bounds write and NULL dereference in the Linux kernel's virtio-net driver, potentially leading to code execution or system crash.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-64552?
CVE-2026-64552 is a high-severity memory corruption vulnerability in Linux, published on 27 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Weakness: CWE-787
Which versions are affected by CVE-2026-64552?
How do I fix CVE-2026-64552?
Apply the vendor's patch.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-64552 being exploited?
There is no known exploitation of CVE-2026-64552 in the wild and no public exploit code.
Sources
Also known as AZL-94029, BELL-CVE-2026-64552, DEBIAN-CVE-2026-64552, GHSA-6c34-77j2-7g8c, ROOT-OS-DEBIAN-12-CVE-2026-64552, UBUNTU-CVE-2026-64552.