MSRC_CVE-2021-31829

Vulnerability from csaf_microsoft - Published: 2021-05-02 00:00 - Updated: 2021-12-16 00:00
Summary
kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads leading to disclosure of stack content via side-channel attacks aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel.

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-2021-31829 kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads leading to disclosure of stack content via side-channel attacks aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-31829.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": "kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads leading to disclosure of stack content via side-channel attacks aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel.",
    "tracking": {
      "current_release_date": "2021-12-16T00:00:00.000Z",
      "generator": {
        "date": "2025-10-19T21:59:28.359Z",
        "engine": {
          "name": "MSRC Generator",
          "version": "1.0"
        }
      },
      "id": "msrc_CVE-2021-31829",
      "initial_release_date": "2021-05-02T00:00:00.000Z",
      "revision_history": [
        {
          "date": "2021-05-14T00:00:00.000Z",
          "legacy_version": "1",
          "number": "1",
          "summary": "Information published."
        },
        {
          "date": "2021-12-16T00:00:00.000Z",
          "legacy_version": "1.1",
          "number": "2",
          "summary": "Added kernel to CBL-Mariner 2.0"
        }
      ],
      "status": "final",
      "version": "2"
    }
  },
  "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 kernel 5.10.60.1-1",
                "product": {
                  "name": "\u003ccm1 kernel 5.10.60.1-1",
                  "product_id": "2"
                }
              },
              {
                "category": "product_version",
                "name": "cm1 kernel 5.10.60.1-1",
                "product": {
                  "name": "cm1 kernel 5.10.60.1-1",
                  "product_id": "16919"
                }
              },
              {
                "category": "product_version_range",
                "name": "\u003ccbl2 kernel 5.10.78.1-1",
                "product": {
                  "name": "\u003ccbl2 kernel 5.10.78.1-1",
                  "product_id": "1"
                }
              },
              {
                "category": "product_version",
                "name": "cbl2 kernel 5.10.78.1-1",
                "product": {
                  "name": "cbl2 kernel 5.10.78.1-1",
                  "product_id": "16920"
                }
              }
            ],
            "category": "product_name",
            "name": "kernel"
          }
        ],
        "category": "vendor",
        "name": "Microsoft"
      }
    ],
    "relationships": [
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccm1 kernel 5.10.60.1-1 as a component of CBL Mariner 1.0",
          "product_id": "16820-2"
        },
        "product_reference": "2",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cm1 kernel 5.10.60.1-1 as a component of CBL Mariner 1.0",
          "product_id": "16919-16820"
        },
        "product_reference": "16919",
        "relates_to_product_reference": "16820"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "\u003ccbl2 kernel 5.10.78.1-1 as a component of CBL Mariner 2.0",
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        },
        "product_reference": "1",
        "relates_to_product_reference": "17086"
      },
      {
        "category": "default_component_of",
        "full_product_name": {
          "name": "cbl2 kernel 5.10.78.1-1 as a component of CBL Mariner 2.0",
          "product_id": "16920-17086"
        },
        "product_reference": "16920",
        "relates_to_product_reference": "17086"
      }
    ]
  },
  "vulnerabilities": [
    {
      "cve": "CVE-2021-31829",
      "cwe": {
        "id": "CWE-863",
        "name": "Incorrect Authorization"
      },
      "notes": [
        {
          "category": "general",
          "text": "mitre",
          "title": "Assigning CNA"
        }
      ],
      "product_status": {
        "fixed": [
          "16919-16820",
          "16920-17086"
        ],
        "known_affected": [
          "16820-2",
          "17086-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-31829 kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads leading to disclosure of stack content via side-channel attacks aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-31829.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-05-14T00:00:00.000Z",
          "details": "-:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "16820-2"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        },
        {
          "category": "vendor_fix",
          "date": "2021-05-14T00:00:00.000Z",
          "details": "5.10.78.1-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
          "product_ids": [
            "17086-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "NONE",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "HIGH",
            "environmentalsScore": 0.0,
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "UNCHANGED",
            "temporalScore": 5.5,
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
            "version": "3.1"
          },
          "products": [
            "16820-2",
            "17086-1"
          ]
        }
      ],
      "title": "kernel/bpf/verifier.c in the Linux kernel through 5.12.1 performs undesirable speculative loads leading to disclosure of stack content via side-channel attacks aka CID-801c6058d14a. The specific concern is not protecting the BPF stack area against speculative loads. Also the BPF stack can contain uninitialized data that might represent sensitive information previously operated on by the kernel."
    }
  ]
}


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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



Detection rules are retrieved from Rulezet.