Linux Kernel up to 7.2.12 KVM SEV gmem sev_gmem_post_populate race condition

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.2.12. It has been declared as very critical. This affects the function sev_gmem_post_populate of the component KVM SEV gmem. The manipulation results in race condition. This vulnerability is reported as CVE-2026-99177. The attack can be launched remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2.12. It has been classified as very critical. Affected is the function sev_gmem_post_populate of the component KVM SEV gmem. The manipulation with an unknown input leads to a race condition vulnerability. CWE is classifying the issue as CWE-362. The product contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently. 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: SEV: Fix page dirtying in sev_gmem_post_populate() set_page_dirty() requires that the caller holds some kind of lock to ensure that the page's mapping does not concurrently go away. That is not the case for a random page we got from get_user_pages_fast(), so use set_page_dirty_lock(). [sean: tag for stable]

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-99177 since 09/25/2026. The exploitability is told to be easy. It is possible to launch the attack 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 10/28/2026).

Upgrading to version 7.2.13 eliminates this vulnerability. Applying the patch 184382f9852d433af21de96c334ecf43b8414ed8/97818b2fa7082e940ddd36dab12a68615300e798 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4
• 7.2.5
• 7.2.6
• 7.2.7
• 7.2.8
• 7.2.9
• 7.2.10
• 7.2.11
• 7.2.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

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