ubuntu-cve-2021-26910
Vulnerability from osv_ubuntu
Published
2021-02-08 20:15
Modified
2025-10-24 04:50
Summary
Details

Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.

Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0 (High)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "firejail",
            "binary_version": "0.9.38.10-0ubuntu0.16.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "firejail",
        "purl": "pkg:deb/ubuntu/firejail@0.9.38.10-0ubuntu0.16.04.1?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.28-1",
        "0.9.32-1",
        "0.9.34-1",
        "0.9.36-1",
        "0.9.38-1",
        "0.9.38-1ubuntu0.1",
        "0.9.38.10-0ubuntu0.16.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "firejail",
            "binary_version": "0.9.52-2"
          },
          {
            "binary_name": "firejail-profiles",
            "binary_version": "0.9.52-2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "firejail",
        "purl": "pkg:deb/ubuntu/firejail@0.9.52-2?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.50-3",
        "0.9.52-1",
        "0.9.52-2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "firejail",
            "binary_version": "0.9.62-3ubuntu0.1"
          },
          {
            "binary_name": "firejail-profiles",
            "binary_version": "0.9.62-3ubuntu0.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "firejail",
        "purl": "pkg:deb/ubuntu/firejail@0.9.62-3ubuntu0.1?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.62-3ubuntu0.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.60-2",
        "0.9.62-1",
        "0.9.62-2",
        "0.9.62-3"
      ]
    }
  ],
  "aliases": [],
  "details": "Firejail before 0.9.64.4 allows attackers to bypass intended access restrictions because there is a TOCTOU race condition between a stat operation and an OverlayFS mount operation.",
  "id": "UBUNTU-CVE-2021-26910",
  "modified": "2025-10-24T04:50:10Z",
  "published": "2021-02-08T20:15:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2021-26910"
    },
    {
      "type": "REPORT",
      "url": "https://www.openwall.com/lists/oss-security/2021/02/08/5"
    },
    {
      "type": "REPORT",
      "url": "https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt"
    },
    {
      "type": "REPORT",
      "url": "https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/"
    },
    {
      "type": "REPORT",
      "url": "http://www.openwall.com/lists/oss-security/2021/02/09/1"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/netblue30/firejail/releases/tag/0.9.64.4"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-5141-1"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2021-26910"
    }
  ],
  "related": [
    "USN-5141-1"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2021-26910"
  ]
}



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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.
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  • 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.


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