KVM: SEV: Reject attempts to sync VMSA of an already-launched/encrypted vCPU

{
  "id": "4a678f223a020aeb02053d18acc3bbed514cfc82ac42dd63a1f4515cc0ec4fee",
  "url": "https://osv.dev/vulnerability/CVE-2026-31593",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "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: 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 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 ",
    "evidence": "osv:CVE-2026-31593",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.83",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.24",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.14",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.1",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-31593",
      "aliases": [
        "CVE-2026-31593"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "ad27ce155566f2b4400fa865859834592bd18777"
                },
                {
                  "fixed": "c9609847ae65ca36233077c2b6cb2bc0fb37c77a"
                },
                {
                  "fixed": "692fdf05e55fa03960a1278afdc2478c12daea13"
                },
                {
                  "fixed": "6ef109e01e1d35199e1a97ea68bdfd3cf3fbf9ab"
                },
                {
                  "fixed": "8f85a4885eee8cb495961ffa371a91828afb9445"
                },
                {
                  "fixed": "9b9f7962e3e879d12da2bf47e02a24ec51690e3d"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31593.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.11.0"
                },
                {
                  "fixed": "6.12.83"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.24"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.14"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.20.0"
                },
                {
                  "fixed": "7.0.1"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31593.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.550524269Z",
      "provider": "osv",
      "references": [
        "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",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31593.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31593",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31593.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31593",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 488506,
  "published_at": "2026-04-24T14:42:19.567+00:00"
}