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CVE-2026-72286
KVM: SEV: Do not allow intra-host migration/mirroring of SNP VMs
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem arch/x86. Debian urgency: unimportant.
What to do, per Debian release
Debian's own status for CVE-2026-72286 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | not affected | 6.1.190-1 | Nothing to do. bookworm never shipped the vulnerable code. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
The intra-host migration/mirroring feature is not fully implemented for SEV-SNP VMs. The proper migration requires additional SNP-specific state such as guest_req_mutex, guest_req_buf, and guest_resp_buf to be transferred or initialized on the destination. The SNP VM mirroring requires vmsa features to be copied as well otherwise ASID would be bound to SNP range while VM is detected as a SEV VM. Reject SNP source VMs in migration/mirroring until proper SNP state transfer is implemented. [sean: let lines poke past 80 chars, tag for stable]
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
arch/x86/kvm/svm/sev.c
- What this is
- KERNEL VIRTUAL MACHINE FOR X86 (KVM/x86)MAINTAINERS section matched on arch/x86/kvm/*/ · kvm@vger.kernel.org · Supported
Show whether Debian builds this, per release
Not established. This site could not find the build rule for the affected file in the kernel trees Debian ships, so it has no answer about whether Debian compiles this code. Read that as unknown, never as absent.
- bookworm, trixie, forky, sid?
- ?
- not established - no Makefile entry for the affected file
Where a release above reads "not established", no build rule for the affected file was found in that release's kernel tree. That is a gap in this lookup, not a finding that the code is absent.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS
Signals
- Published
- 2026-08-15 (2 months ago)source
- CVSS
- 8.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.18%, higher than 6.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- unimportantsource
- Subsystem
- arch/x86
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 6.11 | 6.12.97 | b70404b89daa |
| 6.11 | 6.18.40 | ba06690b28be |
| 6.11 | 7.1.5 | d2f9df3b615c |
| 6.11 | 7.2 | 6ee414078823 |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- The flaw is reached only through KVM_ENABLE_CAP on a VM file descriptor (KVM_CAP_VM_MOVE_ENC_CONTEXT_FROM or KVM_CAP_VM_COPY_ENC_CONTEXT_FROM) after opening /dev/kvm; it is a local ioctl/syscall path, not remote network, adjacent-radio, or physical I/O.
- AC:LAttack complexity, low
- An attacker who controls both source and destination KVM VM fds can deterministically invoke sev_vm_move_enc_context_from() or sev_vm_copy_enc_context_from() on a launched SEV-SNP VM; no race, special memory layout, or other uncontrollable condition is required.
- PR:LPrivileges required, low
- Exploitation requires local /dev/kvm (and /dev/sev) access to create SNP VMs and issue KVM_ENABLE_CAP, privileges commonly granted to kvm-group users, QEMU tenants, or container workloads with KVM passthrough, not real root in the init namespace.
- UI:NUser interaction, none
- No victim user action is required; the attacker’s own VMM process issues the migration/mirroring ioctl sequence directly once it holds the relevant VM file descriptors.
- S:CScope, changed
- Incomplete SNP state transfer crosses the SEV-SNP guest/host trust boundary: mirroring leaves an SNP-bound ASID managed via SEV code paths (missing vmsa_features), and migration leaves destination VMs without snp_context or guest-request buffers.
- C:HConfidentiality impact, high
- SNP/SEV type confusion can undermine SEV-SNP memory isolation and let a hypervisor-side actor access confidential guest memory; missing guest_req_buf/guest_resp_buf and uninitialized mutex also create kernel memory safety failures with disclosure potential.
- I:HIntegrity impact, high
- Inconsistent SNP firmware context and uninitialized guest-request state can corrupt hypervisor memory and guest execution paths during SNP VMGEXIT guest-request handling, enabling modification of protected guest memory and host kernel structures.
- A:HAvailability impact, high
- Migrated SNP VMs reach snp_handle_guest_req() with NULL snp_context/guest_req_buf and an uninitialized guest_req_mutex, which can NULL-dereference or corrupt kernel state and panic/oops the host when the guest issues SNP guest-request VMGEXITs.