FKIE_CVE-2026-31590

Vulnerability from fkie_nvd - Published: 2026-04-24 15:16 - Updated: 2026-04-24 17:51
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION Drop the WARN in sev_pin_memory() on npages overflowing an int, as the WARN is comically trivially to trigger from userspace, e.g. by doing: struct kvm_enc_region range = { .addr = 0, .size = -1ul, }; __vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, &range); Note, the checks in sev_mem_enc_register_region() that presumably exist to verify the incoming address+size are completely worthless, as both "addr" and "size" are u64s and SEV is 64-bit only, i.e. they _can't_ be greater than ULONG_MAX. That wart will be cleaned up in the near future. if (range->addr > ULONG_MAX || range->size > ULONG_MAX) return -EINVAL; Opportunistically add a comment to explain why the code calculates the number of pages the "hard" way, e.g. instead of just shifting @ulen.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1cba4dcd795daf6d257122779fb6a349edf03914
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/28cc13ca20431b127d42d84ba10898d03e2c8267
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/ab423e5892826202a660b5ac85d1125b0e8301a5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/c29ff288a2d97a6f4640a498a367cf0eb91312eb
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{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION\n\nDrop the WARN in sev_pin_memory() on npages overflowing an int, as the\nWARN is comically trivially to trigger from userspace, e.g. by doing:\n\n  struct kvm_enc_region range = {\n          .addr = 0,\n          .size = -1ul,\n  };\n\n  __vm_ioctl(vm, KVM_MEMORY_ENCRYPT_REG_REGION, \u0026range);\n\nNote, the checks in sev_mem_enc_register_region() that presumably exist to\nverify the incoming address+size are completely worthless, as both \"addr\"\nand \"size\" are u64s and SEV is 64-bit only, i.e. they _can\u0027t_ be greater\nthan ULONG_MAX.  That wart will be cleaned up in the near future.\n\n\tif (range-\u003eaddr \u003e ULONG_MAX || range-\u003esize \u003e ULONG_MAX)\n\t\treturn -EINVAL;\n\nOpportunistically add a comment to explain why the code calculates the\nnumber of pages the \"hard\" way, e.g. instead of just shifting @ulen."
    }
  ],
  "id": "CVE-2026-31590",
  "lastModified": "2026-04-24T17:51:40.810",
  "metrics": {},
  "published": "2026-04-24T15:16:36.170",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1cba4dcd795daf6d257122779fb6a349edf03914"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/28cc13ca20431b127d42d84ba10898d03e2c8267"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/ab423e5892826202a660b5ac85d1125b0e8301a5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/c29ff288a2d97a6f4640a498a367cf0eb91312eb"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Awaiting Analysis"
}


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