mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER

{
  "id": "2dd0e43a8cc17fd104d20a5aa37de15fc2e66396d9bb0278d47c1a02a749c07d",
  "url": "https://osv.dev/vulnerability/CVE-2026-43348",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: mshv_vtl: Fix vmemmap_shift exceeding MAX_FOLIO_ORDER When registering VTL0 memory via MSHV_ADD_VTL0_MEMORY, the kernel computes pgmap->vmemmap_shift as the number of trailing zeros in the OR of start_pfn and last_pfn, intending to use the largest compound page order both endpoints are aligned to. However, this value is not clamped to MAX_FOLIO_ORDER, so a sufficiently aligned range (e.g. physical range [0x800000000000, 0x800080000000), corresponding to start_pfn=0x800000000 with 35 trailing zeros) can produce a shift larger than what memremap_pages() accepts, triggering a WARN and returning -EINVAL: WARNING: ... memremap_pages+0x512/0x650 requested folio size unsupported The MAX_FOLIO_ORDER check was added by commit 646b67d57589 (\"mm/memremap: reject unreasonable folio/compound page sizes in memremap_pages()\"). Fix this by clamping vmemmap_shift to MAX_FOLIO_ORDER so we always request the largest order the kernel supports, in those cases, rather than an out-of-range value. Also fix the error path to propagate the actual error code from devm_memremap_pages() instead of hard-coding -EFAULT, which was masking the real -EINVAL return.",
    "evidence": "osv:CVE-2026-43348",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "7.0.2",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-43348",
      "aliases": [
        "CVE-2026-43348"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "7bfe3b8ea6e30437e01fcb8e4f56ef6e4d986d0f"
                },
                {
                  "fixed": "a142ca4b6481e71498712800b20e0c0fcf02843b"
                },
                {
                  "fixed": "404cd6bffe17e25e0f94ed2775ffdd6cd10ac3fd"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43348.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.2"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43348.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.378110806Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/404cd6bffe17e25e0f94ed2775ffdd6cd10ac3fd",
        "https://git.kernel.org/stable/c/a142ca4b6481e71498712800b20e0c0fcf02843b",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43348.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43348",
        "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/2026/43xxx/CVE-2026-43348.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43348",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 500291,
  "published_at": "2026-05-08T13:41:51.909+00:00"
}