CVE-2026-23401 | Linux Kernel up to 7.0-rc5 KVM is_shadow_present_pte memory corruption

VDB-354620 · CVE-2026-23401 · GCVE-0-2026-23401 LINUX KERNEL UP TO 7.0-RC5 KVM IS_SHADOW_PRESENT_PTE MEMORY CORRUPTION HISTORYDIFFRELATEJSONXMLCTI CVSS Meta Temp Score Current Exploit Price (≈) CTI Interest Score 7.6 $5k-$25k 1.71+ Summaryinfo A vulnerability classified as critical was found in Linux Kernel up to 7.0-rc5. This affects the function is_shadow_present_pte of the component KVM. Such manipulation leads to memory corruption. This vulnerability is referenced as CVE-2026-23401. No exploit is available. Upgrading the affected component is advised. Detailsinfo A vulnerability, which was classified as critical, has been found in Linux Kernel up to 7.0-rc5. Affected by this issue is the function is_shadow_present_pte of the component KVM. The manipulation with an unknown input leads to a memory corruption vulnerability. Using CWE to declare the problem leads to CWE-119. The product performs operations on a memory buffer, but it can read from or write to a memory location that is outside of the intended boundary of the buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes: In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Drop/zap existing present SPTE even when creating an MMIO SPTE When installing an emulated MMIO SPTE, do so *after* dropping/zapping the existing SPTE (if it's shadow-present). While commit a54aa15c6bda3 was right about it being impossible to convert a shadow-present SPTE to an MMIO SPTE due to a _guest_ write, it failed to account for writes to guest memory that are outside the scope of KVM. E.g. if host userspace modifies a shadowed gPTE to switch from a memslot to emulted MMIO and then the guest hits a relevant page fault, KVM will install the MMIO SPTE without first zapping the shadow-present SPTE. ------------[ cut here ]------------ is_shadow_present_pte(*sptep) WARNING: arch/x86/kvm/mmu/mmu.c:484 at mark_mmio_spte+0xb2/0xc0 [kvm], CPU#0: vmx_ept_stale_r/4292 Modules linked in: kvm_intel kvm irqbypass CPU: 0 UID: 1000 PID: 4292 Comm: vmx_ept_stale_r Not tainted 7.0.0-rc2-eafebd2d2ab0-sink-vm #319 PREEMPT Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:mark_mmio_spte+0xb2/0xc0 [kvm] Call Trace: mmu_set_spte+0x237/0x440 [kvm] ept_page_fault+0x535/0x7f0 [kvm] kvm_mmu_do_page_fault+0xee/0x1f0 [kvm] kvm_mmu_page_fault+0x8d/0x620 [kvm] vmx_handle_exit+0x18c/0x5a0 [kvm_intel] kvm_arch_vcpu_ioctl_run+0xc55/0x1c20 [kvm] kvm_vcpu_ioctl+0x2d5/0x980 [kvm] __x64_sys_ioctl+0x8a/0xd0 do_syscall_64+0xb5/0x730 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47fa3f ---[ end trace 0000000000000000 ]--- The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2026-23401 since 01/13/2026. The exploitation is known to be easy. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 04/01/2026). Upgrading to version 7.0-rc6 eliminates this vulnerability. Applying the patch aad885e774966e97b675dfe928da164214a71605 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version. Productinfo Type Operating System Vendor Linux Name Kernel Version 7.0-rc1 7.0-rc2 7.0-rc3 7.0-rc4 7.0-rc5 License open-source Website Vendor: https://www.kernel.org/ CPE 2.3info 🔒 🔒 🔒 CPE 2.2info 🔒 🔒 🔒 CVSSv4info VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv3info VulDB Meta Base Score: 8.0 VulDB Meta Temp Score: 7.6 VulDB Base Score: 8.0 VulDB Temp Score: 7.6 VulDB Vector: 🔒 VulDB Reliability: 🔍 CVSSv2info Vector Complexity Authentication Confidentiality Integrity Availability Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock Unlock VulDB Base Score: 🔒 VulDB Temp Score: 🔒 VulDB Reliability: 🔍 Exploitinginfo Class: Memory corruption CWE: CWE-119 CAPEC: 🔒 ATT&CK: 🔒 Physical: No Local: No Remote: Partially Availability: 🔒 Status: Not defined Price Prediction: 🔍 Current Price Estimation: 🔒 0-Day Unlock Unlock Unlock Unlock Today Unlock Unlock Unlock Unlock Threat Intelligenceinfo Interest: 🔍 Active Actors: 🔍 Active APT Groups: 🔍 Countermeasuresinfo Recommended: Upgrade Status: 🔍 0-Day Time: 🔒 Upgrade: Kernel 7.0-rc6 Patch: aad885e774966e97b675dfe928da164214a71605 Timelineinfo 01/13/2026 CVE reserved 04/01/2026 +77 days Advisory disclosed 04/01/2026 +0 days VulDB entry created 04/01/2026 +0 days VulDB entry last update Sourcesinfo Vendor: kernel.org Advisory: git.kernel.org Status: Confirmed CVE: CVE-2026-23401 (🔒) GCVE (CVE): GCVE-0-2026-23401 GCVE (VulDB): GCVE-100-354620 Entryinfo Created: 04/01/2026 11:25 Changes: 04/01/2026 11:25 (59) Complete: 🔍 Cache ID: 99:876:101 Discussion No comments yet. Languages: en. Please log in to comment. ◂ PreviousOverviewNext ▸