{
  "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-2021-3695 A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3695.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 crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12.",
    "tracking": {
      "current_release_date": "2024-06-30T07:00:00.000Z",
      "generator": {
        "date": "2025-10-19T23:43:30.784Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-3695",
      "initial_release_date": "2022-07-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2023-10-05T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2024-06-30T07:00:00.000Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Information published."
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "product_tree": {
    "branches": [
      {
        "branches": [
          {
            "branches": [
              {
                "category": "product_version",
                "name": "3.0",
                "product": {
                  "name": "Azure Linux 3.0",
                  "product_id": "17084"
                }
              }
            ],
            "category": "product_name",
            "name": "Azure Linux"
          },
          {
            "branches": [
              {
                "category": "product_version_range",
                "name": "\u003cazl3 grub2 2.06-23",
                "product": {
                  "name": "\u003cazl3 grub2 2.06-23",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 grub2 2.06-23",
                "product": {
                  "name": "azl3 grub2 2.06-23",
                  "product_id": "19663"
                }
              },
              {
                "category": "product_version_range",
                "name": "\u003cazl3 grub2 2.06-14",
                "product": {
                  "name": "\u003cazl3 grub2 2.06-14",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "azl3 grub2 2.06-14",
                "product": {
                  "name": "azl3 grub2 2.06-14",
                  "product_id": "18842"
                }
              }
            ],
            "category": "product_name",
            "name": "grub2"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003cazl3 grub2 2.06-23 as a component of Azure Linux 3.0",
          "product_id": "17084-1"
        },
        "product_reference": "1",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 grub2 2.06-23 as a component of Azure Linux 3.0",
          "product_id": "19663-17084"
        },
        "product_reference": "19663",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003cazl3 grub2 2.06-14 as a component of Azure Linux 3.0",
          "product_id": "17084-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "17084"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "azl3 grub2 2.06-14 as a component of Azure Linux 3.0",
          "product_id": "18842-17084"
        },
        "product_reference": "18842",
        "relates_to_product_reference": "17084"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-3695",
      "cwe": {
        "id": "CWE-787",
        "name": "Out-of-bounds Write"
      },
      "notes": [
        {
          "category": "general",
          "text": "redhat",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "19663-17084",
          "18842-17084"
        ],
        "known_affected": [
          "17084-1",
          "17084-2"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-3695 A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2022/msrc_cve-2021-3695.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2023-10-05T00:00:00.000Z",
          "details": "2.06-14:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17084-1",
            "17084-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "HIGH",
            "attackVector": "LOCAL",
            "availabilityImpact": "LOW",
            "baseScore": 4.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "LOW",
            "environmentalsScore": 0.0,
            "integrityImpact": "LOW",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "temporalScore": 4.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L",
            "version": "3.1"
          },
          "products": [
            "17084-1",
            "17084-2"
          ]
        }
      ],
      "title": "A crafted 16-bit grayscale PNG image may lead to a out-of-bounds write in the heap area. An attacker may take advantage of that to cause heap data corruption or eventually arbitrary code execution and circumvent secure boot protections. This issue has a high complexity to be exploited as an attacker needs to perform some triage over the heap layout to achieve signifcant results also the values written into the memory are repeated three times in a row making difficult to produce valid payloads. This flaw affects grub2 versions prior grub-2.12."
    }
  ]
}