Issue in the Linux kernel virtio-net/TAP networking path affecting KVM-based hypervisors

Bulletin ID: 2026-137-AWS Scope: AWS Content Type: Important (requires attention) Publication Date: 10/15/2026 10:30 AM PDT Description: AWS is aware of an issue in the Linux kernel's virtio-net/TAP networking path (CVE-2026-99999) that affects KVM-based hypervisors running unpatched Linux kernel versions 4.4 through 6.18. This issue could allow an actor with privileged access inside a guest virtual machine to send specially crafted network packets that corrupt host kernel memory that could result in disclosure of host memory or a denial of service. AWS-managed compute and container services, including Amazon EC2 instances, AWS Lambda, and AWS Fargate, are not affected. There is no action required for customers using these services. Affected products & versions: Customers who self-manage virtual machines using virtio-net and KVM, including those using virtual machine monitors such as Firecracker, on hosts running affected, unpatched Linux kernel versions. Please refer to the article below for the most up-to-date and complete information related to this AWS Security Bulletin.