Linux Kernel up to 6.18.58/7.2.12 KVM nested_ept_get_eptp null pointer dereference

CVSS Meta Temp Score
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CTI Interest Score
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8.4$0-$5k1.02

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel up to 6.18.58/7.2.12. This impacts the function nested_ept_get_eptp of the component KVM. The manipulation results in null pointer dereference. This vulnerability is cataloged as CVE-2026-99176. The attack must be initiated from a local position. There is no exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.18.58/7.2.12. Affected is the function nested_ept_get_eptp of the component KVM. The manipulation with an unknown input leads to a null pointer dereference vulnerability. CWE is classifying the issue as CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: KVM: nVMX: Reset MMU back to the root MMU if loading L2 state fails for !VM-Entry Reset the vCPU's MMU pointer back to the root MMU if loading L2 state fails in the "not from VM-Entry" case, i.e. when emulating RSM or handling KVM_SET_NESTED_STATE. Failure to unwind the MMU pointer results in KVM trying to run L1 with a nested MMU, and is especially problematic if the vCPU manages to free its nested state before the VM crashes. Constructing the root for a nested EPT MMU goes through vmcs12, which is dynamically allocated/freed when nVMX is enabled/disabled. And so if the nested state is freed with the MMU still pointing at the nested MMU, KVM will hit a NULL pointer deref when attempting to get L1=>L2 EPTP. BUG: kernel NULL pointer dereference, address: 0000000000000078 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 114a2d067 P4D 111743067 PUD 11141f067 PMD 0 Oops: Oops: 0000 [#1] SMP CPU: 20 UID: 1000 PID: 1272 Comm: nested_tdp_faul Not tainted 7.3.0-rc4-8c89f11d1a99b-sink-vm #1914 PREEMPTLAZY Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] Call Trace: <TASK> kvm_mmu_load+0xcd/0x870 [kvm] kvm_arch_vcpu_ioctl_run+0x18f5/0x1f80 [kvm] kvm_vcpu_ioctl+0x2c7/0x970 [kvm] __x64_sys_ioctl+0x90/0xd0 do_syscall_64+0x9c/0x4d0 entry_SYSCALL_64_after_hwframe+0x4b/0x53 RIP: 0033:0x47491b </TASK> Modules linked in: kvm_intel kvm irqbypass CR2: 0000000000000078 ---[ end trace 0000000000000000 ]--- RIP: 0010:nested_ept_get_eptp+0xb/0x10 [kvm_intel] [sean: write changelog]

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-99176 since 09/25/2026. The exploitability is told to be easy. Local access is required to approach this attack. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 10/28/2026).

Upgrading to version 6.18.59 or 7.2.13 eliminates this vulnerability. Applying the patch d00d5f534a8238674755e59826a6c7d3c8efb870/c9716f956216eb74ab0aad7f633586edd49e0322/c8f4cfe1cf93bce924e27f2abead7a4c4a487505 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.8
VulDB Meta Temp Score: 8.4

VulDB Base Score: 8.8
VulDB Temp Score: 8.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Null pointer dereference
CWE: CWE-476 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.59/7.2.13
Patch: d00d5f534a8238674755e59826a6c7d3c8efb870/c9716f956216eb74ab0aad7f633586edd49e0322/c8f4cfe1cf93bce924e27f2abead7a4c4a487505

Timelineinfo

09/25/2026 CVE reserved
10/28/2026 +33 days Advisory disclosed
10/28/2026 +0 days VulDB entry created
10/28/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-99176 (🔒)
GCVE (CVE): GCVE-0-2026-99176
GCVE (VulDB): GCVE-100-427854

Entryinfo

Created: 10/28/2026 12:35
Changes: 10/28/2026 12:35 (59)
Complete: 🔍
Cache ID: 216::103

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