CVE-2026-31593 (GCVE-0-2026-31593)

Vulnerability from cvelistv5 – Published: 2026-04-24 14:42 – Updated: 2026-04-24 14:42
VLAI?
Title
KVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU
Summary
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. 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> 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().
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < c9609847ae65ca36233077c2b6cb2bc0fb37c77a (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 692fdf05e55fa03960a1278afdc2478c12daea13 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 8f85a4885eee8cb495961ffa371a91828afb9445 (git)
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    Linux Linux Unaffected: 6.12.83 , ≤ 6.12.* (semver)
Unaffected: 6.18.24 , ≤ 6.18.* (semver)
Unaffected: 6.19.14 , ≤ 6.19.* (semver)
Unaffected: 7.0.1 , ≤ 7.0.* (semver)
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
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          "programFiles": [
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          "vendor": "Linux",
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              "status": "unaffected",
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              "versionType": "semver"
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              "versionType": "semver"
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      "cpeApplicability": [
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      "descriptions": [
        {
          "lang": "en",
          "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   \u003cTASK\u003e\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   \u003c/TASK\u003e\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()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-24T14:42:19.567Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/c9609847ae65ca36233077c2b6cb2bc0fb37c77a"
        },
        {
          "url": "https://git.kernel.org/stable/c/692fdf05e55fa03960a1278afdc2478c12daea13"
        },
        {
          "url": "https://git.kernel.org/stable/c/6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab"
        },
        {
          "url": "https://git.kernel.org/stable/c/8f85a4885eee8cb495961ffa371a91828afb9445"
        }
      ],
      "title": "KVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU",
      "x_generator": {
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      }
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  "cveMetadata": {
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-31593",
    "datePublished": "2026-04-24T14:42:19.567Z",
    "dateReserved": "2026-03-09T15:48:24.121Z",
    "dateUpdated": "2026-04-24T14:42:19.567Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
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      "date": "2026-04-26",
      "epss": "0.00018",
      "percentile": "0.0462"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-31593\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-24T15:16:36.957\",\"lastModified\":\"2026-04-24T17:51:40.810\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"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   \u003cTASK\u003e\\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   \u003c/TASK\u003e\\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().\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/692fdf05e55fa03960a1278afdc2478c12daea13\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/8f85a4885eee8cb495961ffa371a91828afb9445\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/c9609847ae65ca36233077c2b6cb2bc0fb37c77a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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