USN-4915-1 (UBUNTU-CVE-2021-3492)

Vulnerability from osv_ubuntu – Published: 2021-04-15 22:22 – Updated: 2026-06-03 10:45 – Source website
VLAI
Summary
linux-oem-5.6 vulnerabilities
Details

It was discovered that the overlayfs implementation in the Linux kernel did not properly validate the application of file system capabilities with respect to user namespaces. A local attacker could use this to gain elevated privileges. (CVE-2021-3493)

Vincent Dehors discovered that the shiftfs file system in the Ubuntu Linux kernel did not properly handle faults in copy_from_user() when passing through ioctls to an underlying file system. A local attacker could use this to cause a denial of service (memory exhaustion) or execute arbitrary code. (CVE-2021-3492)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2021-3492",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "high",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2021-3493",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "high",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "linux-buildinfo-5.6.0-1054-oem",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-headers-5.6.0-1054-oem",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-image-unsigned-5.6.0-1054-oem",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-modules-5.6.0-1054-oem",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-oem-5.6-headers-5.6.0-1054",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-oem-5.6-tools-5.6.0-1054",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-oem-5.6-tools-host",
            "binary_version": "5.6.0-1054.58"
          },
          {
            "binary_name": "linux-tools-5.6.0-1054-oem",
            "binary_version": "5.6.0-1054.58"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "linux-oem-5.6",
        "purl": "pkg:deb/ubuntu/linux-oem-5.6@5.6.0-1054.58?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5.6.0-1054.58"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5.6.0-1007.7",
        "5.6.0-1008.8",
        "5.6.0-1010.10",
        "5.6.0-1011.11",
        "5.6.0-1013.13",
        "5.6.0-1017.17",
        "5.6.0-1018.18",
        "5.6.0-1020.20",
        "5.6.0-1021.21",
        "5.6.0-1023.23",
        "5.6.0-1026.26",
        "5.6.0-1027.27",
        "5.6.0-1028.28",
        "5.6.0-1031.32",
        "5.6.0-1032.33",
        "5.6.0-1033.35",
        "5.6.0-1034.36",
        "5.6.0-1035.37",
        "5.6.0-1036.39",
        "5.6.0-1039.43",
        "5.6.0-1042.46",
        "5.6.0-1047.51",
        "5.6.0-1048.52",
        "5.6.0-1050.54",
        "5.6.0-1052.56",
        "5.6.0-1053.57"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that the overlayfs implementation in the Linux kernel did\nnot properly validate the application of file system capabilities with\nrespect to user namespaces. A local attacker could use this to gain\nelevated privileges. (CVE-2021-3493)\n\nVincent Dehors discovered that the shiftfs file system in the Ubuntu Linux\nkernel did not properly handle faults in copy_from_user() when passing\nthrough ioctls to an underlying file system. A local attacker could use\nthis to cause a denial of service (memory exhaustion) or execute arbitrary\ncode. (CVE-2021-3492)\n",
  "id": "USN-4915-1",
  "modified": "2026-06-03T10:45:25Z",
  "published": "2021-04-15T22:22:20Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-4915-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-3492"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-3493"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "linux-oem-5.6 vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2021-3492",
    "UBUNTU-CVE-2021-3493"
  ]
}



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