The Linux kernel had a vulnerability (CVE-2026-74406) in the VXLAN code where a race condition could cause a null pointer dereference in vxlan_gro_prepare_receive(). Specifically, udp_tunnel_sock_release() could set the socket's sk_user_data pointer to NULL concurrently while vxlan_gro_prepare_receive() was running, leading to a potential crash or undefined behavior. The fix involved verifying that the pointer returned by rcu_dereference_sk_user_data() is not NULL after skb_gro_remcsum_init() to prevent dereferencing a null pointer.

This vulnerability could cause a kernel crash or instability due to a null pointer dereference in the VXLAN network code. There is no information about exploitation in the wild or further impact such as privilege escalation or data leakage.

A fix has been applied to the Linux kernel to address this issue by adding a null check in vxlan_gro_prepare_receive(). Users should update to the fixed kernel version once available. Patch status is not explicitly confirmed in the provided data; check the vendor advisory for current remediation guidance.