CVE-2025-40292

About vulnerability

In the Linux kernel, the following vulnerability has been resolved: virtio-net: fix received length check in big packets Since commit 4959aebba8c0 (“virtio-net: use mtu size as buffer length for big packets”), when guest gso is off, the allocated size for big packets is not MAX_SKB_FRAGS * PAGE_SIZE anymore but depends on negotiated MTU. The number of allocated frags for big packets is stored in vi->big_packets_num_skbfrags. Because the host announced buffer length can be malicious (e.g. the host vhost_net driver’s get_rx_bufs is modified to announce incorrect length), we need a check in virtio_net receive path. Currently, the check is not adapted to the new change which can lead to NULL page pointer dereference in the below while loop when receiving length that is larger than the allocated one. This commit fixes the received length check corresponding to the new change. A null pointer dereference was found in the virtio-net driver in the Linux kernel. When receiving big packets, the length validation does not account for the MTU-based buffer sizing changes. A malicious host can announce incorrect buffer lengths, causing the driver to access NULL page pointers when processing oversized packets.

Live-patch status from KernelCare for each operating system.