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KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION

Type: advisorySources: OSV

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.

Products
Kernel
Affected versions
Not specified
Fixed versions
5.10.258, 5.15.209, 6.1.175, 6.12.83, 6.18.24, 6.19.14, 6.6.136, 7.0.1
CVEs
CVE-2026-31590
Confirmed fixed CVEs
Not specified
Updated in this feed
8 Nov 2026, 01:59 UTC · Revision 1

Source evidence

KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION

core-osv · Original source

Published 24 Apr 2026, 14:42 UTC

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.

osv:CVE-2026-31590

Kernel

Fixed versions: 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0.1

Complete source record
{
  "id": "b1e4864579bf7b6e82b5d9b4d87633a6103fd5969996f4125803b1e1b981a528",
  "url": "https://osv.dev/vulnerability/CVE-2026-31590",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION",
    "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.",
    "evidence": "osv:CVE-2026-31590",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "5.10.258",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "5.15.209",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.1.175",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.136",
            "evidence": "/affected/1/ranges"
          },
          {
            "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-2026-31590",
      "aliases": [
        "CVE-2026-31590"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "78824fabc72e5e37d51e6e567fde70a4fc41a6d7"
                },
                {
                  "fixed": "6a8e3c82122737529b25ef2a048fbcc569d8c055"
                },
                {
                  "fixed": "a703933bcfa5cc76ca10e2048464600e74136099"
                },
                {
                  "fixed": "abcd43ff579abd0a654bb4636086e78819dd5f4c"
                },
                {
                  "fixed": "b670833749ffd8681361db2bb047c6f2e3075f3a"
                },
                {
                  "fixed": "ab423e5892826202a660b5ac85d1125b0e8301a5"
                },
                {
                  "fixed": "28cc13ca20431b127d42d84ba10898d03e2c8267"
                },
                {
                  "fixed": "c29ff288a2d97a6f4640a498a367cf0eb91312eb"
                },
                {
                  "fixed": "1cba4dcd795daf6d257122779fb6a349edf03914"
                },
                {
                  "fixed": "8acffeef5ef720c35e513e322ab08e32683f32f2"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-31590.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.9.0"
                },
                {
                  "fixed": "5.10.258"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.11.0"
                },
                {
                  "fixed": "5.15.209"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "5.16.0"
                },
                {
                  "fixed": "6.1.175"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.2.0"
                },
                {
                  "fixed": "6.6.136"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "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-2026-31590.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.757670605Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1cba4dcd795daf6d257122779fb6a349edf03914",
        "https://git.kernel.org/stable/c/28cc13ca20431b127d42d84ba10898d03e2c8267",
        "https://git.kernel.org/stable/c/6a8e3c82122737529b25ef2a048fbcc569d8c055",
        "https://git.kernel.org/stable/c/8acffeef5ef720c35e513e322ab08e32683f32f2",
        "https://git.kernel.org/stable/c/a703933bcfa5cc76ca10e2048464600e74136099",
        "https://git.kernel.org/stable/c/ab423e5892826202a660b5ac85d1125b0e8301a5",
        "https://git.kernel.org/stable/c/abcd43ff579abd0a654bb4636086e78819dd5f4c",
        "https://git.kernel.org/stable/c/b670833749ffd8681361db2bb047c6f2e3075f3a",
        "https://git.kernel.org/stable/c/c29ff288a2d97a6f4640a498a367cf0eb91312eb",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/31xxx/CVE-2026-31590.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-31590",
        "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-2026-31590.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-31590",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 521574,
  "published_at": "2026-04-24T14:42:17.629+00:00"
}