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CVE-2021-3492 (GCVE-0-2021-3492)

Vulnerability from cvelistv5 – Published: 2021-04-17 04:20 – Updated: 2024-09-17 03:54
VLAI
Title
Ubuntu linux kernel shiftfs file system double free vulnerability
Summary
Shiftfs, an out-of-tree stacking file system included in Ubuntu Linux kernels, did not properly handle faults occurring during copy_from_user() correctly. These could lead to either a double-free situation or memory not being freed at all. An attacker could use this to cause a denial of service (kernel memory exhaustion) or gain privileges via executing arbitrary code. AKA ZDI-CAN-13562.
Severity
8.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
CWE
  • CWE-415 - Double Free
  • CWE-401 - Missing Release of Memory after Effective Lifetime
Assigner
References
Impacted products
Vendor Product Version CPE status
Ubuntu Linux kernel Affected: 5.8 kernel , < 5.8.0-50.56 (custom)
Affected: 5.4 kernel , < 5.4.0-72.80 (custom)
guessed Create a notification for this product.
Date Public
2021-04-15 00:00
Credits
Vincent Dehors of Synactiv Digital Security
Show details on NVD website
To clipboard 

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        "lastModified": "2024-11-21T06:21:40.257",
        "metrics": {
          "cvssMetricV2": [
            {
              "acInsufInfo": false,
              "baseSeverity": "HIGH",
              "cvssData": {
                "accessComplexity": "LOW",
                "accessVector": "LOCAL",
                "authentication": "NONE",
                "availabilityImpact": "COMPLETE",
                "baseScore": 7.2,
                "confidentialityImpact": "COMPLETE",
                "integrityImpact": "COMPLETE",
                "vectorString": "AV:L/AC:L/Au:N/C:C/I:C/A:C",
                "version": "2.0"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 10.0,
              "obtainAllPrivilege": false,
              "obtainOtherPrivilege": false,
              "obtainUserPrivilege": false,
              "source": "nvd@nist.gov",
              "type": "Primary",
              "userInteractionRequired": false
            }
          ],
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 8.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 2.0,
              "impactScore": 6.0,
              "source": "security@ubuntu.com",
              "type": "Secondary"
            },
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.9,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ]
        },
        "published": "2021-04-17T05:15:13.113",
        "references": [
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Third Party Advisory",
              "VDB Entry"
            ],
            "url": "http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html"
          },
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Mailing List",
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333"
          },
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Mailing List",
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6"
          },
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://ubuntu.com/security/notices/USN-4917-1"
          },
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://www.openwall.com/lists/oss-security/2021/04/16/2"
          },
          {
            "source": "security@ubuntu.com",
            "tags": [
              "Third Party Advisory",
              "VDB Entry"
            ],
            "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-422/"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Third Party Advisory",
              "VDB Entry"
            ],
            "url": "http://packetstormsecurity.com/files/162614/Kernel-Live-Patch-Security-Notice-LSN-0077-1.html"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Mailing List",
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=25c891a949bf918b59cbc6e4932015ba4c35c333"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Mailing List",
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/focal/commit/?id=8fee52ab9da87d82bc6de9ebb3480fff9b4d53e6"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Vendor Advisory"
            ],
            "url": "https://ubuntu.com/security/notices/USN-4917-1"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Mailing List",
              "Third Party Advisory"
            ],
            "url": "https://www.openwall.com/lists/oss-security/2021/04/16/2"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Third Party Advisory",
              "VDB Entry"
            ],
            "url": "https://www.zerodayinitiative.com/advisories/ZDI-21-422/"
          }
        ],
        "sourceIdentifier": "security@ubuntu.com",
        "vulnStatus": "Modified",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-401"
              },
              {
                "lang": "en",
                "value": "CWE-415"
              }
            ],
            "source": "security@ubuntu.com",
            "type": "Secondary"
          },
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-401"
              },
              {
                "lang": "en",
                "value": "CWE-415"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-06-28T06:25:40+00:00",
      "cve": "CVE-2021-3492",
      "id": "CVE-2021-3492",
      "initial_release_date": "2021-04-16T00:00:00+00:00",
      "product_status:known_not_affected": "197",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: shiftfs file system double free vulnerability",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-3492.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-25T17:45:32Z",
      "cve": "CVE-2021-3492",
      "id": "CVE-2021-3492",
      "initial_release_date": "2023-02-15T03:49:22Z",
      "product_status:known_not_affected": "320",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-3492",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-3492.json",
      "version": "14"
    }
  }
}



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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.