GHSA-WV9V-6465-83FW

Vulnerability from github – Published: 2026-07-25 12:31 – Updated: 2026-07-25 12:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

crypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)

Sashiko notes:

if SEV initialization fails and KVM is actively running normal VMs, could a userspace process trigger this code path via /dev/sev ioctls (e.g., SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN execution for an active VM trigger a general protection fault and crash the host?

Refuse to re-try initialization if SNP is not already initialized for SNP_CONFIG.

This is technically an ABI break: before if SNP initialization failed it could be transparently retriggered by this ioctl, and if no VMs were running, everything worked fine. Hopefully this is enough of a corner case that nobody will notice, but someone does, there are a few options:

  • do something like symbol_get() for kvm and refuse to initialize if KVM is loaded
  • check each cpu's HSAVE_PA for non-zero data before re-initializing
  • once initialization has failed, continue to refuse to initialize until the ccp module is unloaded
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{
  "affected": [],
  "aliases": [
    "CVE-2026-64307"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-25T10:17:11Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ncrypto: ccp - Do not initialize SNP for ioctl(SNP_CONFIG)\n\nSashiko notes:\n\n\u003e if SEV initialization fails and KVM is actively running normal VMs, could a\n\u003e userspace process trigger this code path via /dev/sev ioctls (e.g.,\n\u003e SEV_PDH_GEN) and zero out MSR_VM_HSAVE_PA globally? Would the next VMRUN\n\u003e execution for an active VM trigger a general protection fault and crash the\n\u003e host?\n\nRefuse to re-try initialization if SNP is not already initialized for\nSNP_CONFIG.\n\nThis is technically an ABI break: before if SNP initialization failed it\ncould be transparently retriggered by this ioctl, and if no VMs were\nrunning, everything worked fine. Hopefully this is enough of a corner case\nthat nobody will notice, but someone does, there are a few options:\n\n* do something like symbol_get() for kvm and refuse to initialize if KVM is\n  loaded\n* check each cpu\u0027s HSAVE_PA for non-zero data before re-initializing\n* once initialization has failed, continue to refuse to initialize until\n  the ccp module is unloaded",
  "id": "GHSA-wv9v-6465-83fw",
  "modified": "2026-07-25T12:31:30Z",
  "published": "2026-07-25T12:31:30Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64307"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/08f0e65e784c4b20e6e620dd4f68d8636073a3d2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/20f548cdac94860a164e5ebba4f7e4a01051cb06"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/345a6e869b33687e9268044bcaeeefd7c61da675"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/441ea32cf2755a0dc593557056b00b7caa0651f5"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}



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