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CVE-2026-31593

Estado: AnalizadaMedia (5.5)—

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

Probabilidad de explotación (EPSS)

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

Referencias

JSON original (NVD)

Mostrar
{
  "id": "CVE-2026-31593",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
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        "type": "Primary",
        "source": "nvd@nist.gov",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 5.5,
          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "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",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 3.6,
        "exploitabilityScore": 1.8
      }
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          "vendor": "Linux",
          "product": "Linux",
          "versions": [
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            },
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            },
            {
              "status": "unaffected",
              "version": "6.12.83",
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              "lessThanOrEqual": "6.12.*"
            },
            {
              "status": "unaffected",
              "version": "6.18.24",
              "versionType": "semver",
              "lessThanOrEqual": "6.18.*"
            },
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              "version": "6.19.14",
              "versionType": "semver",
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              "status": "unaffected",
              "version": "7.0.1",
              "versionType": "semver",
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "arch/x86/kvm/svm/sev.c"
          ],
          "defaultStatus": "affected"
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  "published": "2026-04-24T15:16:36.957",
  "references": [
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  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
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          "lang": "en",
          "value": "NVD-CWE-noinfo"
        }
      ]
    }
  ],
  "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   <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": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "ABF3F6D0-27D6-43E7-BF38-1B493B03EC1F",
              "versionEndExcluding": "6.12.83",
              "versionStartIncluding": "6.11"
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "vulnerable": true,
              "matchCriteriaId": "8126B8B8-6D0B-4443-86C1-672AEE893555",
              "versionEndExcluding": "6.18.24",
              "versionStartIncluding": "6.13"
            },
            {
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              "vulnerable": true,
              "matchCriteriaId": "D6A8A074-BBF4-4803-ABED-519A839435BB",
              "versionEndExcluding": "6.19.14",
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              "versionEndExcluding": "7.0.1",
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          "operator": "OR"
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}