Vghost Linux flaw can give local users root and threaten VM hosts
CVE-2026-74580 affects Linux vhost code across almost a decade of kernels, with a fix available and vendor patches arriving.
A Linux kernel flaw tracked as CVE-2026-74580 can let a local attacker read and write kernel memory, escalate to root and, in a specific virtual-machine configuration, attack the host's QEMU process.12
Why Vghost matters
The vulnerability sits in Linux's vhost subsystem, which accelerates I/O for virtual machines and containers. A stale metadata-cache entry can survive changes to a virtual ring's address or size, allowing later reads and writes to use an old translation without a fresh bounds check.12
The local attack affects kernels from Linux 4.11 through 7.2-rc4. Tencent's researchers reproduced it across Ubuntu, Red Hat Enterprise Linux, Amazon Linux, Azure Linux and Oracle Linux images. In a virtualised setup with a virtual IOMMU and the required virtio configuration, an untrusted guest can trigger a related host-side write into the QEMU process.12
Patch and mitigation
The upstream fix is commit de845981da67, which clears the cache when the ring is reconfigured. Red Hat and other vendors have shipped or backported fixes, but version numbers may not change when a vendor applies the patch.13
Until a fixed kernel is installed and the machine rebooted, administrators should restrict access to /dev/vhost-net and /dev/vhost-vsock, remove world permissions and limit membership of the owning group to trusted virtualisation services.13
Our opinion
The important detail here is not the novelty of an AI-assisted discovery pipeline; it is the age and reach of the bug. Virtualisation is often treated as a hard boundary, yet a small cache-invalidation mistake can turn a device intended to move data into a route across that boundary. Operators should treat the kernel update and device-node permissions as urgent maintenance, not as optional hardening.