Local kernel compromise via KVM memslot flag clearing
Published Jan 13, 2026 · Updated Jan 13, 2026
Use-after-free in KVM in Linux Kernel allows local users to corrupt kernel memory through a guest_memfd memslot flags change. The KVM_SET_USER_MEMORY_REGION2 path accepts clearing KVM_MEM_GUEST_MEMFD on an existing bound memslot without unbinding its guest_memfd, leaving kvm_gmem_release to write through freed storage. Exploitation requires local access able to issue KVM VM ioctls; successful exploitation compromises confidentiality, integrity, and availability in the host kernel.
Summary
What happened
Use-after-free in KVM in Linux Kernel allows local users to corrupt kernel memory through a guest_memfd memslot flags change. The KVM_SET_USER_MEMORY_REGION2 path accepts clearing KVM_MEM_GUEST_MEMFD on an existing bound memslot without unbinding its guest_memfd, leaving kvm_gmem_release to write through freed storage. Exploitation requires local access able to issue KVM VM ioctls; successful exploitation compromises confidentiality, integrity, and availability in the host kernel.
The record
- CVE
- CVE-2025-68810
- Published
- Jan 13, 2026
- Updated
- Jan 13, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 13, 2026CVE publishedPublication date reported by the CVE source.
- Jan 13, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=6.8
- Affected versionversion=a7800aa80ea4d5356b8474c2302812e9d4926fa6 <89dbbe6ff323fc34659621a577fe0af913f47386
- Affected versionversion=a7800aa80ea4d5356b8474c2302812e9d4926fa6 <9935df5333aa503a18de5071f53762b65c783c4c
- Affected versionversion=a7800aa80ea4d5356b8474c2302812e9d4926fa6 <cb51bef465d8ec60a968507330e01020e35dc127
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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