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CVE-2026-74580, widely known as Vghost, represents a critical security flaw residing within the vhost subsystem of the Linux kernel.
The vulnerability originates from how virtqueue ring addresses or descriptor configurations are modified using ioctl commands like VHOST_SET_VRING_ADDR and VHOST_SET_VRING_NUM.
Specifically, when these ring configurations are updated, the kernel’s internal caching mechanism for Input/Output Translation Lookaside Buffer metadata—tracked via vq->meta_iotlb[]—fails to properly invalidate previously cached descriptor, available-ring, and used-ring mappings.
Because the stale cache persists, subsequent descriptor fetches or used-ring updates can reference memory regions completely outside the intended IOTLB-mapped boundaries.
This flawed state allows local unprivileged users who possess access to vhost device nodes to achieve arbitrary kernel memory reads and writes.
Consequently, attackers can bypass Kernel Address Space Layout Randomization (KASLR) and seamlessly escalate their privileges to root on the host machine.
Furthermore, in specific virtualization setups where a virtual IOMMU, iommu_platform, and virtio queue-reset capabilities are enabled, this same stale-cache flaw can be triggered from inside a guest virtual machine.
This cross-boundary trigger introduces a severe guest-to-host escape vector, potentially overwriting host QEMU process memory and hijacking control flow or causing denial of service.
The vulnerability impacts a massive range of upstream Linux kernels spanning from version 4.11 up to 7.2-rc4, making it a widespread architectural concern across enterprise virtualization environments.
Remediation requires applying the official kernel patches that properly invalidate metadata caches upon ring modifications and restricting permissions on vhost device nodes.
DailyCVE Form:
Platform: Linux kernel vhost
Version: 4.11 through 7.2
Vulnerability: Stale IOTLB cache
Severity: Critical
date: October 14, 2026
Prediction: Patched already released
What Undercode Say:
Bash Commands And Codes
Check loaded vhost modules lsmod | grep vhost Check permissions on vhost character devices ls -la /dev/vhost- Inspect kernel version to check vulnerability window uname -r
Exploit: (Educational Purposes!)
The exploit leverages the `VHOST_SET_VRING_ADDR` ioctl to reconfigure virtqueue structures without flushing the underlying `meta_iotlb[]` cache. By supplying manipulated addresses, an attacker forces the vhost driver to treat unmapped or sensitive kernel memory regions as valid ring buffers. This permits direct read/write primitives against kernel structures, allowing the modification of security tokens like `modprobe_path` to achieve root execution.
Protection: From This CVE
- Update the Linux kernel to versions containing the official upstream patch that forces IOTLB cache invalidation during ring updates.
- Restrict access permissions on vhost device nodes (
/dev/vhost-) to prevent unprivileged local users from opening them. - Disable vulnerable virtual device configurations involving virtual IOMMUs and `iommu_platform` for untrusted virtual machine guests until hosts are patched.
Impact:
Full local privilege escalation to root on vulnerable Linux host systems.
Complete bypass of KASLR and kernel memory integrity boundaries.
Potential guest-to-host virtual machine escape, corrupting host hypervisor memory and hijacking QEMU control flow.
Widespread exposure affecting enterprise virtualization infrastructure running unpatched Linux kernels over a multi-year window.
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Sources:
Reported By: github.com
Extra Source Hub:
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