msrc_cve-2021-3748
Vulnerability from csaf_microsoft
Published
2022-03-02 00:00
Modified
2023-03-10 00:00
Summary
A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor's address belongs to the non direct access region due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU resulting in a denial of service condition or potentially execute code on the host with the privileges of the QEMU process.

Notes

Additional Resources
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer
The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.


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{
  "document": {
    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
      }
    },
    "lang": "en-US",
    "notes": [
      {
        "category": "general",
        "text": "To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle",
        "title": "Additional Resources"
      },
      {
        "category": "legal_disclaimer",
        "text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
        "title": "Disclaimer"
      }
    ],
    "publisher": {
      "category": "vendor",
      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2021-3748 A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor\u0027s address belongs to the non direct access region due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU resulting in a denial of service condition or potentially execute code on the host with the privileges of the QEMU process. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3748.json"
      },
      {
        "category": "external",
        "summary": "Microsoft Support Lifecycle",
        "url": "https://support.microsoft.com/lifecycle"
      },
      {
        "category": "external",
        "summary": "Common Vulnerability Scoring System",
        "url": "https://www.first.org/cvss"
      }
    ],
    "title": "A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor\u0027s address belongs to the non direct access region due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU resulting in a denial of service condition or potentially execute code on the host with the privileges of the QEMU process.",
    "tracking": {
      "current_release_date": "2023-03-10T00:00:00.000Z",
      "generator": {
        "date": "2025-10-19T23:23:33.140Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-3748",
      "initial_release_date": "2022-03-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2023-03-10T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "1"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "1.0",
                "product": {
                  "name": "CBL Mariner 1.0",
                  "product_id": "16820"
                }
              },
              {
                "category": "product_version",
                "name": "2.0",
                "product": {
                  "name": "CBL Mariner 2.0",
                  "product_id": "17086"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003ccm1 qemu-kvm 4.2.0-39",
                "product": {
                  "name": "\u003ccm1 qemu-kvm 4.2.0-39",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "cm1 qemu-kvm 4.2.0-39",
                "product": {
                  "name": "cm1 qemu-kvm 4.2.0-39",
                  "product_id": "18887"
                }
              }
            ],
            "category": "product_name",
            "name": "qemu-kvm"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003ccbl2 qemu 6.2.0-2",
                "product": {
                  "name": "\u003ccbl2 qemu 6.2.0-2",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "cbl2 qemu 6.2.0-2",
                "product": {
                  "name": "cbl2 qemu 6.2.0-2",
                  "product_id": "18757"
                }
              }
            ],
            "category": "product_name",
            "name": "qemu"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccm1 qemu-kvm 4.2.0-39 as a component of CBL Mariner 1.0",
          "product_id": "16820-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cm1 qemu-kvm 4.2.0-39 as a component of CBL Mariner 1.0",
          "product_id": "18887-16820"
        },
        "product_reference": "18887",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccbl2 qemu 6.2.0-2 as a component of CBL Mariner 2.0",
          "product_id": "17086-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 qemu 6.2.0-2 as a component of CBL Mariner 2.0",
          "product_id": "18757-17086"
        },
        "product_reference": "18757",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-3748",
      "cwe": {
        "id": "CWE-416",
        "name": "Use After Free"
      },
      "notes": [
        {
          "category": "general",
          "text": "redhat",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "18887-16820",
          "18757-17086"
        ],
        "known_affected": [
          "16820-1",
          "17086-2"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-3748 A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor\u0027s address belongs to the non direct access region due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU resulting in a denial of service condition or potentially execute code on the host with the privileges of the QEMU process. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3748.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2023-03-10T00:00:00.000Z",
          "details": "4.2.0-39:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        },
        {
          "category": "vendor_fix",
          "date": "2023-03-10T00:00:00.000Z",
          "details": "6.2.0-2:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17086-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "temporalScore": 7.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "products": [
            "16820-1",
            "17086-2"
          ]
        }
      ],
      "title": "A use-after-free vulnerability was found in the virtio-net device of QEMU. It could occur when the descriptor\u0027s address belongs to the non direct access region due to num_buffers being set after the virtqueue elem has been unmapped. A malicious guest could use this flaw to crash QEMU resulting in a denial of service condition or potentially execute code on the host with the privileges of the QEMU process."
    }
  ]
}


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