CVE-2026-31593
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU
Reject synchronizing vCPU state to its associated VMSA if the vCPU has already been launched, i.e. if the VMSA has already been encrypted. On a host with SNP enabled, accessing guest-private memory generates an RMP #PF and panics the host.
Note, the KVM flaw has been present since commit ad73109ae7ec ("KVM: SVM: Provide support to launch and run an SEV-ES guest"), but has only been actively dangerous for the host since SNP support was added. With SEV-ES, KVM would "just" clobber guest state, which is totally fine from a host kernel perspective since userspace can clobber guest state any time before sev_launch_update_vmsa().
Detalles técnicos trazas, registros y código del informe original
BUG: unable to handle page fault for address: ff1276cbfdf36000 #PF: supervisor write access in kernel mode #PF: error_code(0x80000003) - RMP violation PGD 5a31801067 P4D 5a31802067 PUD 40ccfb5063 PMD 40e5954063 PTE 80000040fdf36163 SEV-SNP: PFN 0x40fdf36, RMP entry: [0x6010fffffffff001 - 0x000000000000001f] Oops: Oops: 0003 [#1] SMP NOPTI CPU: 33 UID: 0 PID: 996180 Comm: qemu-system-x86 Tainted: G OE Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE Hardware name: Dell Inc. PowerEdge R7625/0H1TJT, BIOS 1.5.8 07/21/2023 RIP: 0010:sev_es_sync_vmsa+0x54/0x4c0 [kvm_amd] Call Trace: <TASK> snp_launch_update_vmsa+0x19d/0x290 [kvm_amd] snp_launch_finish+0xb6/0x380 [kvm_amd] sev_mem_enc_ioctl+0x14e/0x720 [kvm_amd] kvm_arch_vm_ioctl+0x837/0xcf0 [kvm] kvm_vm_ioctl+0x3fd/0xcc0 [kvm] __x64_sys_ioctl+0xa3/0x100 x64_sys_call+0xfe0/0x2350 do_syscall_64+0x81/0x10f0 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7ffff673287d </TASK>
CVSS
- Versión: 3.1
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- Puntuación base: 5.5
Probabilidad de explotación (EPSS)
- Probabilidad de explotación en los próximos 30 días: 0.16%
- Percentil entre todas las CVEs puntuadas: 5
- Fecha de la puntuación: 6/10/2026
EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).
Tecnologías afectadas (1)
CWE
- NVD-CWE-noinfo
Referencias
- https://git.kernel.org/stable/c/692fdf05e55fa03960a1278afdc2478c12daea13
- https://git.kernel.org/stable/c/6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab
- https://git.kernel.org/stable/c/8f85a4885eee8cb495961ffa371a91828afb9445
- https://git.kernel.org/stable/c/9b9f7962e3e879d12da2bf47e02a24ec51690e3d
- https://git.kernel.org/stable/c/c9609847ae65ca36233077c2b6cb2bc0fb37c77a
JSON original (NVD)
Mostrar
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"integrityImpact": "NONE",
"userInteraction": "NONE",
"attackComplexity": "LOW",
"availabilityImpact": "HIGH",
"privilegesRequired": "LOW",
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"descriptions": [
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU\n\nReject synchronizing vCPU state to its associated VMSA if the vCPU has\nalready been launched, i.e. if the VMSA has already been encrypted. On a\nhost with SNP enabled, accessing guest-private memory generates an RMP #PF\nand panics the host.\n\n BUG: unable to handle page fault for address: ff1276cbfdf36000\n #PF: supervisor write access in kernel mode\n #PF: error_code(0x80000003) - RMP violation\n PGD 5a31801067 P4D 5a31802067 PUD 40ccfb5063 PMD 40e5954063 PTE 80000040fdf36163\n SEV-SNP: PFN 0x40fdf36, RMP entry: [0x6010fffffffff001 - 0x000000000000001f]\n Oops: Oops: 0003 [#1] SMP NOPTI\n CPU: 33 UID: 0 PID: 996180 Comm: qemu-system-x86 Tainted: G OE\n Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE\n Hardware name: Dell Inc. PowerEdge R7625/0H1TJT, BIOS 1.5.8 07/21/2023\n RIP: 0010:sev_es_sync_vmsa+0x54/0x4c0 [kvm_amd]\n Call Trace:\n <TASK>\n snp_launch_update_vmsa+0x19d/0x290 [kvm_amd]\n snp_launch_finish+0xb6/0x380 [kvm_amd]\n sev_mem_enc_ioctl+0x14e/0x720 [kvm_amd]\n kvm_arch_vm_ioctl+0x837/0xcf0 [kvm]\n kvm_vm_ioctl+0x3fd/0xcc0 [kvm]\n __x64_sys_ioctl+0xa3/0x100\n x64_sys_call+0xfe0/0x2350\n do_syscall_64+0x81/0x10f0\n entry_SYSCALL_64_after_hwframe+0x76/0x7e\n RIP: 0033:0x7ffff673287d\n </TASK>\n\nNote, the KVM flaw has been present since commit ad73109ae7ec (\"KVM: SVM:\nProvide support to launch and run an SEV-ES guest\"), but has only been\nactively dangerous for the host since SNP support was added. With SEV-ES,\nKVM would \"just\" clobber guest state, which is totally fine from a host\nkernel perspective since userspace can clobber guest state any time before\nsev_launch_update_vmsa()."
}
],
"lastModified": "2026-06-17T10:34:02.900",
"configurations": [
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