FKIE_CVE-2026-52959

Vulnerability from fkie_nvd - Published: 2026-06-24 17:17 - Updated: 2026-06-28 08:16
Severity
7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: virt: sev-guest: Do not use host-controlled page order in cleanup path When issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST), get_ext_report() allocates a buffer to retrieve a certificate blob from the host, keeping track of its size in report_req->certs_len. However, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating an invalid buffer size, as well as the expected length of such buffer. get_ext_report() subsequently updates report_req->certs_len with the host-controlled value, and cleans up the buffer by computing a page order from such value. This is incorrect, as the host-provided length may not match the page order of the original allocation, potentially resulting in corruption in the page allocator. Fix this by using alloc_pages_exact() instead, and reusing @npages to compute the size passed to free_pages_exact(). For consistency, also use @npages to compute the size when allocating the pages, even though this last change has no functional effect.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/23e6a1ca04ae44806439a5a446e62e4d42e80bb4
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3f6fb0211b39aaa1b841260681dd02ca6b693ed5
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9e48b4f813d2c3db75d522aa82ab705ce04b7e2d
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/virt/coco/sev-guest/sev-guest.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "3f6fb0211b39aaa1b841260681dd02ca6b693ed5",
              "status": "affected",
              "version": "3e385c0d6ce88ac9916dcf84267bd5855d830748",
              "versionType": "git"
            },
            {
              "lessThan": "9e48b4f813d2c3db75d522aa82ab705ce04b7e2d",
              "status": "affected",
              "version": "3e385c0d6ce88ac9916dcf84267bd5855d830748",
              "versionType": "git"
            },
            {
              "lessThan": "23e6a1ca04ae44806439a5a446e62e4d42e80bb4",
              "status": "affected",
              "version": "3e385c0d6ce88ac9916dcf84267bd5855d830748",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "0b16521f95c875e79d657cb8d6911c15080dbb80",
              "versionType": "git"
            },
            {
              "lessThan": "6.14",
              "status": "affected",
              "version": "6.13.8",
              "versionType": "semver"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/virt/coco/sev-guest/sev-guest.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.33",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.10",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirt: sev-guest: Do not use host-controlled page order in cleanup path\n\nWhen issuing an extended guest request (SVM_VMGEXIT_EXT_GUEST_REQUEST),\nget_ext_report() allocates a buffer to retrieve a certificate blob from the\nhost, keeping track of its size in report_req-\u003ecerts_len.\n\nHowever, the host may return SNP_GUEST_VMM_ERR_INVALID_LEN, indicating\nan invalid buffer size, as well as the expected length of such buffer.\nget_ext_report() subsequently updates report_req-\u003ecerts_len with the\nhost-controlled value, and cleans up the buffer by computing a page order\nfrom such value. This is incorrect, as the host-provided length may not\nmatch the page order of the original allocation, potentially resulting\nin corruption in the page allocator.\n\nFix this by using alloc_pages_exact() instead, and reusing @npages to\ncompute the size passed to free_pages_exact(). For consistency, also\nuse @npages to compute the size when allocating the pages, even though\nthis last change has no functional effect."
    }
  ],
  "id": "CVE-2026-52959",
  "lastModified": "2026-06-28T08:16:26.690",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-06-24T17:17:06.157",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/23e6a1ca04ae44806439a5a446e62e4d42e80bb4"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3f6fb0211b39aaa1b841260681dd02ca6b693ed5"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9e48b4f813d2c3db75d522aa82ab705ce04b7e2d"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}


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