msrc_cve-2021-26931
Vulnerability from csaf_microsoft
Published
2021-02-02 00:00
Modified
2021-02-25 00:00
Summary
An issue was discovered in the Linux kernel 2.6.39 through 5.10.16 as used in Xen. Block net and SCSI backends consider certain errors a plain bug deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions) it isn't correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c.

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.


To clipboard 

{
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    "category": "csaf_vex",
    "csaf_version": "2.0",
    "distribution": {
      "text": "Public",
      "tlp": {
        "label": "WHITE",
        "url": "https://www.first.org/tlp/"
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        "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": {
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      "contact_details": "secure@microsoft.com",
      "name": "Microsoft Security Response Center",
      "namespace": "https://msrc.microsoft.com"
    },
    "references": [
      {
        "category": "self",
        "summary": "CVE-2021-26931 An issue was discovered in the Linux kernel 2.6.39 through 5.10.16 as used in Xen. Block net and SCSI backends consider certain errors a plain bug deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions) it isn\u0027t correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c. - VEX",
        "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-26931.json"
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  "vulnerabilities": [
    {
      "cve": "CVE-2021-26931",
      "cwe": {
        "id": "CWE-770",
        "name": "Allocation of Resources Without Limits or Throttling"
      },
      "notes": [
        {
          "category": "general",
          "text": "mitre",
          "title": "Assigning CNA"
        }
      ],
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          "13859-12138",
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          "13862-12138",
          "13863-12138",
          "13864-12138",
          "13865-12138",
          "13866-12138"
        ],
        "known_affected": [
          "12137-16",
          "12137-15",
          "12137-14",
          "12137-13",
          "12137-12",
          "12137-11",
          "12137-10",
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          "12138-6",
          "12138-5",
          "12138-4",
          "12138-3",
          "12138-2",
          "12138-1"
        ]
      },
      "references": [
        {
          "category": "self",
          "summary": "CVE-2021-26931 An issue was discovered in the Linux kernel 2.6.39 through 5.10.16 as used in Xen. Block net and SCSI backends consider certain errors a plain bug deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions) it isn\u0027t correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c. - VEX",
          "url": "https://msrc.microsoft.com/csaf/vex/2021/msrc_cve-2021-26931.json"
        }
      ],
      "remediations": [
        {
          "category": "vendor_fix",
          "date": "2021-02-25T00:00:00.000Z",
          "details": "-:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
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            "12137-13",
            "12137-12",
            "12137-11",
            "12137-10",
            "12137-9",
            "12138-8",
            "12138-7",
            "12138-6",
            "12138-5",
            "12138-4",
            "12138-3",
            "12138-2",
            "12138-1"
          ],
          "url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
        }
      ],
      "scores": [
        {
          "cvss_v3": {
            "attackComplexity": "LOW",
            "attackVector": "LOCAL",
            "availabilityImpact": "HIGH",
            "baseScore": 5.5,
            "baseSeverity": "MEDIUM",
            "confidentialityImpact": "NONE",
            "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:N/I:N/A:H",
            "version": "3.1"
          },
          "products": [
            "12137-16",
            "12137-15",
            "12137-14",
            "12137-13",
            "12137-12",
            "12137-11",
            "12137-10",
            "12137-9",
            "12138-8",
            "12138-7",
            "12138-6",
            "12138-5",
            "12138-4",
            "12138-3",
            "12138-2",
            "12138-1"
          ]
        }
      ],
      "title": "An issue was discovered in the Linux kernel 2.6.39 through 5.10.16 as used in Xen. Block net and SCSI backends consider certain errors a plain bug deliberately causing a kernel crash. For errors potentially being at least under the influence of guests (such as out of memory conditions) it isn\u0027t correct to assume a plain bug. Memory allocations potentially causing such crashes occur only when Linux is running in PV mode though. This affects drivers/block/xen-blkback/blkback.c and drivers/xen/xen-scsiback.c."
    }
  ]
}


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