Januscape

Januscape: Guest-to-Host Escape in KVM/x86 Abstract This document describes the Januscape CVE-2026-53359 vulnerability discovered and reported by Hyunwoo Kim @v4bel. It is a KVM escape vulnerability that lets a guest escape to the host in a KVM/x86 environment. To the best of public knowledge, th...

CVE-2021-3656-Demo

CVE-2021-3656: This issue is caused by missing validation of the the virtext VMCB field and allows a malicious L1 guest to disable both VMLOAD/VMSAVE intercepts and VLS Virtual VMLOAD/VMSAVE for the L2 guest. Under these circumstances, the L2 guest is able to run VMLOAD/VMSAVE unintercepted, and...

hyperv_local_dos_poc

Hyper-V DoS PoC. This is code files of Visual Studio 2019 driver project. 1. Compile driver. 2. Enable nested virtualization for guest OS using command: root@kitploit: Set-VMProcessor -VMName -ExposeVirtualizationExtensions $true 3. Run driver inside guest OS. Host OS will be rebooted or generate...

Zapscape

The KVM Escape Trilogy ITScape CVE‑2026‑46316 | Januscape CVE‑2026‑53359 | Zapscape CVE‑2026‑64561 ---|---|--- Zapscape: Guest-to-Host Escape in KVM/x86 Abstract This document describes the Zapscape CVE-2026-64561 vulnerability discovered and reported by Hyunwoo Kim @v4bel. It is a KVM escape...

New Linux Kernel Flaw Gives ARM64 KVM Guests Read-Write Access to Host Memory

A new flaw in the Linux kernel's KVM virtualization code for ARM64 processors can leave a freed piece of host memory exposed to a guest virtual machine on hosts with nested virtualization enabled. The bug, tracked as CVE-2026-89775, allows a guest to read and write host kernel memory, and the...

KVM-Januscape

KVM-XJ Hot Patch dumptool.py automatically finds offsets; how to use it? Just read the code. Vulnerability Overview CVE-2026-53359 Januscape is a use-after-free UAF vulnerability in the Linux kernel KVM shadow MMU. Lurking time : 16 years August 2010 to July 2026 Affected range : All Intel/AMD x8...

CVE-2026-64561

CVE-2026-64561 — Zapscape: KVM/x86 shadow MMU UAF, guest escape to host root HackSpeak distribution mirror. This repository is a distribution mirror of the complete PoC + technical write-up publicly released by researcher Hyunwoo Kim @v4bel , with code and documentation identical to upstream. ⚠️...

kernel: KVM: x86: Don't (re)check L1 intercepts when completing userspace I/O

A flaw was found in the Kernel-based Virtual Machine KVM for x86. This vulnerability occurs when KVM incorrectly re-checks Level 1 L1 intercepts during the completion of userspace I/O emulation for a Level 2 L2 instruction. If the L1 or host userspace modifies I/O interception settings during thi...

DEBIAN-CVE-2026-89929

In the Linux kernel, the following vulnerability has been resolved: KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU When emulating INVVPID, KVM executes INVVPID on the physical CPU using vpid02 instead of the L1 assigned VPID, after doing some validations on the operands. However...

AZL-101610 CVE-2026-89932 affecting package kernel 6.6.152.1-1

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Always flush vpid02 on first use Make sure vpid02 is always flushed on first use by setting lastvpid=0 when allocating vpid02. nestedvmxtransitiontlbflush will always detect a VPID change on first VM-Enter after VMXON,...

CVE-2026-89932 KVM: nVMX: Always flush vpid02 on first use

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Always flush vpid02 on first use Make sure vpid02 is always flushed on first use by setting lastvpid=0 when allocating vpid02. nestedvmxtransitiontlbflush will always detect a VPID change on first VM-Enter after VMXON,...

EUVD-2026-80532

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Always flush vpid02 on first use Make sure vpid02 is always flushed on first use by setting lastvpid=0 when allocating vpid02. nestedvmxtransitiontlbflush will always detect a VPID change on first VM-Enter after VMXON,...

CVE-2026-89929

CVE-2026-89929 affects the Linux kernel KVM subsystem, specifically the nested virtualization (nVM ) code path that emulates the INVVPID instruction. When a guest L1 vCPU migrates between physical CPUs and issues INVVPID, KVM executes the instruction on the current physical CPU rather than the on...

Linux Distros Unpatched Vulnerability : CVE-2026-89929

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available. - KVM: nVM: Ensure INVVPID is emulated on the correct physical CPU When emulating INVVPID, KVM executes INVVPID on the physical CPU using vpid02 instead of the L1...

kernel: KVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation

A flaw was found in the Linux kernel's Kernel-based Virtual Machine KVM nSVM module. When a nested virtual machine L2 guest executes VMSAVE/VMLOAD instructions, and these are not intercepted by the first-level hypervisor L1, KVM incorrectly uses vmcb02 instead of vmcb01 for managing guest state...

kernel: KVM: nSVM: Always use vmcb01 in VMLOAD/VMSAVE emulation

A flaw was found in the Linux kernel's Kernel-based Virtual Machine KVM nSVM module. When a nested virtual machine L2 guest executes VMSAVE/VMLOAD instructions, and these are not intercepted by the first-level hypervisor L1, KVM incorrectly uses vmcb02 instead of vmcb01 for managing guest state...

Astra Linux – Vulnerability in Linux

A flaw was discovered in the KVM’s AMD code, responsible for supporting SVM nested virtualization. The flaw occurs during the processing of the VMCB virtual machine control block provided by the L1 guest, which is used to spawn or handle a nested guest L2. Due to improper validation of the “intct...

Astra Linux – Vulnerability in Linux 5.15

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Warns when a triple fault assertion never “escapes” from L2 The warnings are removed because they perform a sanity check that ensures KVM never allows a triple fault in L2 to escape and end up in L1. In normal operation...

Astra Linux – Vulnerability in Linux 5.10

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Forcibly leave nested virtualization mode when SMM state is toggled The nested virtualization mode is forcibly exited if the user space toggles the SMM state using KVMSETVCPUEVENTS or KVMSYNCX86EVENTS. If the user space...

Astra Linux – Vulnerability in Linux 6.1

In the Linux kernel, the following vulnerability has been resolved: KVM: nSVM: Remove the user-triggered WARN message emitted by nestedsvmloadcr3. Remove the WARN message generated by svmsetnestedstate in nestedsvmloadcr3 failure cases. This message can be easily triggered from userspace by...