CVE-2026-64104 (GCVE-0-2026-64104)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
8.7 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L
Summary
In the Linux kernel, the following vulnerability has been resolved: virt: sev-guest: Explicitly leak pages in unknown state When set_memory_{encrypted,decrypted}() fail, the user cannot know at which point the function failed, meaning that the pages are left in an unknown state from the point of view of the caller. Since the pages may be left in an unencrypted state, they are not suitable for general use, and cannot be returned safely to the buddy allocator. Avoid the issue by never freeing the pages, and then do the proper accounting by calling snp_leak_pages().
References
Impacted products
Vendor Product Version
Linux Linux Version: 3e385c0d6ce88ac9916dcf84267bd5855d830748
Version: 3e385c0d6ce88ac9916dcf84267bd5855d830748
Version: 3e385c0d6ce88ac9916dcf84267bd5855d830748
Version: 0b16521f95c875e79d657cb8d6911c15080dbb80
Version: 6.13.8   ≤
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "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": [
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              "lessThan": "bee400ad4f4259c9c0758e4f1960a1eed6f6f9f0",
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              "versionType": "git"
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              "lessThan": "3d0cd0065deeb054b4b29236432e851806b7cc81",
              "status": "affected",
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              "versionType": "git"
            },
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              "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": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.34",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0.11",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.1",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionStartIncluding": "6.13.8",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvirt: sev-guest: Explicitly leak pages in unknown state\n\nWhen set_memory_{encrypted,decrypted}() fail, the user cannot know at which\npoint the function failed, meaning that the pages are left in an unknown state\nfrom the point of view of the caller.\n\nSince the pages may be left in an unencrypted state, they are not suitable for\ngeneral use, and cannot be returned safely to the buddy allocator. Avoid the\nissue by never freeing the pages, and then do the proper accounting by calling\nsnp_leak_pages()."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.7,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:L",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is in `get_ext_report()` and is reached only via `SNP_GET_EXT_REPORT` ioctl on `/dev/sev-guest` (or the kernel-internal configfs-TSM path), which requires local access inside an AMD SEV-SNP confidential guest VM.\nAC:L - A local caller can repeatedly issue `SNP_GET_EXT_REPORT` with a non-zero, page-aligned `certs_len` to drive allocation and `set_memory_decrypted()`/`set_memory_encrypted()`; on failure after `snp_set_memory_shared()` has already run, the pre-fix path incorrectly returned those pages to the buddy allocator.\nPR:L - Exploitation requires opening `/dev/sev-guest` and issuing the ioctl; in typical confidential-VM deployments attestation is performed by unprivileged workloads, and the ioctl path does not require real root in the init namespace.\nUI:N - Triggering the vulnerable cleanup requires only programmatic ioctl calls to obtain an extended attestation report; no victim user action such as mounting a filesystem or opening a file is needed.\nS:C - Returning pages that may remain in shared/unencrypted RMP state to the buddy allocator breaks the SEV-SNP guest-to-hypervisor memory confidentiality boundary, allowing a malicious or compromised hypervisor to read (and tamper with) guest kernel memory later allocated on those pages.\nC:H - Pages can be left hypervisor-visible while re-entering the general kernel page pool, enabling disclosure of arbitrary subsequent guest kernel memory contents (keys, crypto material, process data) to the untrusted host.\nI:H - Shared RMP pages reused by the kernel can be modified by the hypervisor before the guest reads them, providing a write primitive against guest kernel memory that can undermine integrity of kernel data structures and potentially enable further compromise.\nA:L - The flaw does not directly panic the kernel, but repeated triggering of the error path can stress page accounting and, in worst cases, contribute to allocator instability; availability impact is limited rather than a reliable crash."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:15.778Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bee400ad4f4259c9c0758e4f1960a1eed6f6f9f0"
        },
        {
          "url": "https://git.kernel.org/stable/c/3d0cd0065deeb054b4b29236432e851806b7cc81"
        },
        {
          "url": "https://git.kernel.org/stable/c/fd948c3f96b18ff9ba7d3e8eae13d196593e1aaf"
        }
      ],
      "title": "virt: sev-guest: Explicitly leak pages in unknown state",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64104",
    "datePublished": "2026-07-19T15:40:07.994Z",
    "dateReserved": "2026-07-19T07:54:57.034Z",
    "dateUpdated": "2026-08-05T12:39:15.778Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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