Linux Kernel up to 7.1.12 KVM kvm_gfn_is_write_tracked improper synchronization

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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6.2$0-$5k0.74+

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.1.186/6.6.155/6.12.107/6.18.48/7.1.12 and classified as critical. This impacts the function kvm_gfn_is_write_tracked of the component KVM. Executing a manipulation can lead to improper synchronization. This vulnerability is registered as CVE-2026-98164. It is possible to launch the attack remotely. No exploit is available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 6.1.186/6.6.155/6.12.107/6.18.48/7.1.12. This vulnerability affects the function kvm_gfn_is_write_tracked of the component KVM. The manipulation with an unknown input leads to a improper synchronization vulnerability. The CWE definition for the vulnerability is CWE-662. The product utilizes multiple threads or processes to allow temporary access to a shared resource that can only be exclusive to one process at a time, but it does not properly synchronize these actions, which might cause simultaneous accesses of this resource by multiple threads or processes. As an impact it is known to affect availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: KVM: x86/mmu: Check write tracking in all address spaces kvm_gfn_is_write_tracked() checks only the supplied memslot, but page tracking is per-address-space and shadow pages are shared across all address spaces. With SMM, a GFN can therefore be write-tracked in one address space and appear untracked through the other. Check the supplied slot first, then the slot for the other address space. This ensures all callers honor write tracking regardless of the active address space. In particular, it prevents mmu_try_to_unsync_pages() from marking an upper-level shadow page unsync and eventually triggering the BUG in pte_list_remove(). [invert direction of the conditional. - Paolo]

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-98164 since 09/25/2026. The exploitation appears to be easy. The attack can be initiated remotely. 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 09/29/2026).

Upgrading to version 6.1.187, 6.6.156, 6.12.108, 6.18.49 or 7.1.13 eliminates this vulnerability. Applying the patch 09aa68552d2542cc6c23edd1568ac265dc5d886f/429b6f43b4d8c98988fdca99e02dc156134e3d77/d8636c8f9f95d0fd1e2f6f1cad0d5757aa6f212a/c0a9bd5fca0b5f2dea32b0fc31350e71e8648112/ec8fcaf354c1cbb36755d48e9f5a00c9591349e5/0f38453cdb2e17566ccb7c0f3dabd5bd21caca26 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: 6.5
VulDB Meta Temp Score: 6.2

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Improper synchronization
CWE: CWE-662
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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 6.1.187/6.6.156/6.12.108/6.18.49/7.1.13
Patch: 09aa68552d2542cc6c23edd1568ac265dc5d886f/429b6f43b4d8c98988fdca99e02dc156134e3d77/d8636c8f9f95d0fd1e2f6f1cad0d5757aa6f212a/c0a9bd5fca0b5f2dea32b0fc31350e71e8648112/ec8fcaf354c1cbb36755d48e9f5a00c9591349e5/0f38453cdb2e17566ccb7c0f3dabd5bd21caca26

Timelineinfo

09/25/2026 CVE reserved
09/29/2026 +4 days Advisory disclosed
09/29/2026 +0 days VulDB entry created
09/29/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-98164 (🔒)
GCVE (CVE): GCVE-0-2026-98164
GCVE (VulDB): GCVE-100-411310

Entryinfo

Created: 09/29/2026 14:34
Changes: 09/29/2026 14:34 (59)
Complete: 🔍
Cache ID: 216::103

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