CVE-2021-3996 (GCVE-0-2021-3996)

Vulnerability from cvelistv5 – Published: 2022-08-23 00:00 – Updated: 2024-10-15 15:26
VLAI
Summary
A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users' filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.
Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: poc Automatable: no Technical Impact: partial
CISA Coordinator (v2.0.3)
CWE
  • CWE-552 - - Files or Directories Accessible to External Parties
Assigner
References
Impacted products
Vendor Product Version
n/a util-linux Affected: Fixed in util-linux v2.37.3
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T17:16:02.913Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://www.openwall.com/lists/oss-security/2022/01/24/2"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2024628"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://access.redhat.com/security/cve/CVE-2021-3996"
          },
          {
            "name": "[oss-security] 20221130 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)",
            "tags": [
              "mailing-list",
              "x_transferred"
            ],
            "url": "http://www.openwall.com/lists/oss-security/2022/11/30/2"
          },
          {
            "name": "20221208 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)",
            "tags": [
              "mailing-list",
              "x_transferred"
            ],
            "url": "http://seclists.org/fulldisclosure/2022/Dec/4"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://security.netapp.com/advisory/ntap-20221209-0002/"
          },
          {
            "name": "GLSA-202401-08",
            "tags": [
              "vendor-advisory",
              "x_transferred"
            ],
            "url": "https://security.gentoo.org/glsa/202401-08"
          }
        ],
        "title": "CVE Program Container"
      },
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "LOCAL",
              "availabilityImpact": "HIGH",
              "baseScore": 5.5,
              "baseSeverity": "MEDIUM",
              "confidentialityImpact": "NONE",
              "integrityImpact": "NONE",
              "privilegesRequired": "LOW",
              "scope": "UNCHANGED",
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2021-3996",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-03-04T21:16:28.797475Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-10-15T15:26:56.079Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "util-linux",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "Fixed in util-linux v2.37.3"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users\u0027 filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-552",
              "description": "CWE-552 - Files or Directories Accessible to External Parties",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2024-01-07T09:06:22.825Z",
        "orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
        "shortName": "redhat"
      },
      "references": [
        {
          "url": "https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes"
        },
        {
          "url": "https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb"
        },
        {
          "url": "https://www.openwall.com/lists/oss-security/2022/01/24/2"
        },
        {
          "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2024628"
        },
        {
          "url": "https://access.redhat.com/security/cve/CVE-2021-3996"
        },
        {
          "name": "[oss-security] 20221130 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)",
          "tags": [
            "mailing-list"
          ],
          "url": "http://www.openwall.com/lists/oss-security/2022/11/30/2"
        },
        {
          "name": "20221208 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)",
          "tags": [
            "mailing-list"
          ],
          "url": "http://seclists.org/fulldisclosure/2022/Dec/4"
        },
        {
          "url": "http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html"
        },
        {
          "url": "https://security.netapp.com/advisory/ntap-20221209-0002/"
        },
        {
          "name": "GLSA-202401-08",
          "tags": [
            "vendor-advisory"
          ],
          "url": "https://security.gentoo.org/glsa/202401-08"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749",
    "assignerShortName": "redhat",
    "cveId": "CVE-2021-3996",
    "datePublished": "2022-08-23T00:00:00.000Z",
    "dateReserved": "2021-11-22T00:00:00.000Z",
    "dateUpdated": "2024-10-15T15:26:56.079Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-3996",
      "date": "2026-06-05",
      "epss": "0.00171",
      "percentile": "0.3822"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-3996\",\"sourceIdentifier\":\"secalert@redhat.com\",\"published\":\"2022-08-23T20:15:08.560\",\"lastModified\":\"2024-11-21T06:23:20.377\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users\u0027 filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.\"},{\"lang\":\"es\",\"value\":\"Se ha encontrado un error l\u00f3gico en la biblioteca libmount de util-linux en la funci\u00f3n que permite a un usuario no privilegiado desmontar un sistema de archivos FUSE. Este fallo permite a un usuario local en un sistema vulnerable desmontar los sistemas de archivos de otros usuarios que son de escritura mundial (como /tmp) o que est\u00e1n montados en un directorio de escritura mundial. Un atacante puede usar este fallo para causar una denegaci\u00f3n de servicio a las aplicaciones que usan los sistemas de archivos afectados.\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6},{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\",\"baseScore\":5.5,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"NONE\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":3.6}]},\"weaknesses\":[{\"source\":\"secalert@redhat.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-552\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-552\"}]}],\"configurations\":[{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:a:kernel:util-linux:*:*:*:*:*:*:*:*\",\"versionStartIncluding\":\"2.34\",\"versionEndExcluding\":\"2.37.3\",\"matchCriteriaId\":\"755D0AAC-24D9-4B39-BCC2-06AC9FF889E2\"}]}]},{\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"80E516C0-98A4-4ADE-B69F-66A772E2BAAA\"}]}]}],\"references\":[{\"url\":\"http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"http://seclists.org/fulldisclosure/2022/Dec/4\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"http://www.openwall.com/lists/oss-security/2022/11/30/2\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://access.redhat.com/security/cve/CVE-2021-3996\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Issue Tracking\",\"Third Party Advisory\"]},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=2024628\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Issue Tracking\",\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Release Notes\",\"Vendor Advisory\"]},{\"url\":\"https://security.gentoo.org/glsa/202401-08\",\"source\":\"secalert@redhat.com\"},{\"url\":\"https://security.netapp.com/advisory/ntap-20221209-0002/\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Broken Link\",\"Third Party Advisory\"]},{\"url\":\"https://www.openwall.com/lists/oss-security/2022/01/24/2\",\"source\":\"secalert@redhat.com\",\"tags\":[\"Exploit\",\"Mailing List\",\"Patch\",\"Third Party Advisory\"]},{\"url\":\"http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Third Party Advisory\"]},{\"url\":\"http://seclists.org/fulldisclosure/2022/Dec/4\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"http://www.openwall.com/lists/oss-security/2022/11/30/2\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Mailing List\",\"Third Party Advisory\"]},{\"url\":\"https://access.redhat.com/security/cve/CVE-2021-3996\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Issue Tracking\",\"Third Party Advisory\"]},{\"url\":\"https://bugzilla.redhat.com/show_bug.cgi?id=2024628\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Issue Tracking\",\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Patch\",\"Third Party Advisory\"]},{\"url\":\"https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Release Notes\",\"Vendor Advisory\"]},{\"url\":\"https://security.gentoo.org/glsa/202401-08\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\"},{\"url\":\"https://security.netapp.com/advisory/ntap-20221209-0002/\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Broken Link\",\"Third Party Advisory\"]},{\"url\":\"https://www.openwall.com/lists/oss-security/2022/01/24/2\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Exploit\",\"Mailing List\",\"Patch\",\"Third Party Advisory\"]}]}}",
    "vulnrichment": {
      "containers": "{\"adp\": [{\"title\": \"CVE Program Container\", \"references\": [{\"url\": \"https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://www.openwall.com/lists/oss-security/2022/01/24/2\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2024628\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://access.redhat.com/security/cve/CVE-2021-3996\", \"tags\": [\"x_transferred\"]}, {\"url\": \"http://www.openwall.com/lists/oss-security/2022/11/30/2\", \"name\": \"[oss-security] 20221130 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)\", \"tags\": [\"mailing-list\", \"x_transferred\"]}, {\"url\": \"http://seclists.org/fulldisclosure/2022/Dec/4\", \"name\": \"20221208 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)\", \"tags\": [\"mailing-list\", \"x_transferred\"]}, {\"url\": \"http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://security.netapp.com/advisory/ntap-20221209-0002/\", \"tags\": [\"x_transferred\"]}, {\"url\": \"https://security.gentoo.org/glsa/202401-08\", \"name\": \"GLSA-202401-08\", \"tags\": [\"vendor-advisory\", \"x_transferred\"]}], \"providerMetadata\": {\"orgId\": \"af854a3a-2127-422b-91ae-364da2661108\", \"shortName\": \"CVE\", \"dateUpdated\": \"2024-08-03T17:16:02.913Z\"}}, {\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 5.5, \"attackVector\": \"LOCAL\", \"baseSeverity\": \"MEDIUM\", \"vectorString\": \"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H\", \"integrityImpact\": \"NONE\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"confidentialityImpact\": \"NONE\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2021-3996\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"poc\"}, {\"Automatable\": \"no\"}, {\"Technical Impact\": \"partial\"}], \"version\": \"2.0.3\", \"timestamp\": \"2024-03-04T21:16:28.797475Z\"}}}], \"providerMetadata\": {\"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"shortName\": \"CISA-ADP\", \"dateUpdated\": \"2024-10-15T15:26:41.487Z\"}}], \"cna\": {\"affected\": [{\"vendor\": \"n/a\", \"product\": \"util-linux\", \"versions\": [{\"status\": \"affected\", \"version\": \"Fixed in util-linux v2.37.3\"}]}], \"references\": [{\"url\": \"https://mirrors.edge.kernel.org/pub/linux/utils/util-linux/v2.37/v2.37.3-ReleaseNotes\"}, {\"url\": \"https://github.com/util-linux/util-linux/commit/166e87368ae88bf31112a30e078cceae637f4cdb\"}, {\"url\": \"https://www.openwall.com/lists/oss-security/2022/01/24/2\"}, {\"url\": \"https://bugzilla.redhat.com/show_bug.cgi?id=2024628\"}, {\"url\": \"https://access.redhat.com/security/cve/CVE-2021-3996\"}, {\"url\": \"http://www.openwall.com/lists/oss-security/2022/11/30/2\", \"name\": \"[oss-security] 20221130 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)\", \"tags\": [\"mailing-list\"]}, {\"url\": \"http://seclists.org/fulldisclosure/2022/Dec/4\", \"name\": \"20221208 Race condition in snap-confine\u0027s must_mkdir_and_open_with_perms() (CVE-2022-3328)\", \"tags\": [\"mailing-list\"]}, {\"url\": \"http://packetstormsecurity.com/files/170176/snap-confine-must_mkdir_and_open_with_perms-Race-Condition.html\"}, {\"url\": \"https://security.netapp.com/advisory/ntap-20221209-0002/\"}, {\"url\": \"https://security.gentoo.org/glsa/202401-08\", \"name\": \"GLSA-202401-08\", \"tags\": [\"vendor-advisory\"]}], \"descriptions\": [{\"lang\": \"en\", \"value\": \"A logic error was found in the libmount library of util-linux in the function that allows an unprivileged user to unmount a FUSE filesystem. This flaw allows a local user on a vulnerable system to unmount other users\u0027 filesystems that are either world-writable themselves (like /tmp) or mounted in a world-writable directory. An attacker may use this flaw to cause a denial of service to applications that use the affected filesystems.\"}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-552\", \"description\": \"CWE-552 - Files or Directories Accessible to External Parties\"}]}], \"providerMetadata\": {\"orgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"shortName\": \"redhat\", \"dateUpdated\": \"2024-01-07T09:06:22.825Z\"}}}",
      "cveMetadata": "{\"cveId\": \"CVE-2021-3996\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2024-10-15T15:26:56.079Z\", \"dateReserved\": \"2021-11-22T00:00:00.000Z\", \"assignerOrgId\": \"53f830b8-0a3f-465b-8143-3b8a9948e749\", \"datePublished\": \"2022-08-23T00:00:00.000Z\", \"assignerShortName\": \"redhat\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.