Security advisory

{
  "id": "c059c991b2fcb0169a5c247b9d51f354b90ac8cd8eecea85c467bc27f4656761",
  "url": "https://osv.dev/vulnerability/CVE-2021-26910",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-26910",
    "summary": "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.",
    "evidence": "osv:CVE-2021-26910",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-26910",
      "aliases": [
        "CVE-2021-26910"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/netblue30/firejail",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "b818fc40cef9865b3202b7de227348dd26acf9fd"
                },
                {
                  "fixed": "97d8a03cad19501f017587cc4e47d8418273834b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:firejail_project:firejail:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.9.64.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "97d8a03cad19501f017587cc4e47d8418273834b"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b818fc40cef9865b3202b7de227348dd26acf9fd"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "0.9.64.4"
                  }
                ]
              }
            }
          ],
          "versions": [
            "0.9.64.2",
            "0.9.64",
            "0.9.64rc1",
            "0.9.60",
            "0.9.60-rc1",
            "0.9.58.2",
            "0.9.58",
            "0.9.58-rc1",
            "0.9.56",
            "0.9.56-rc1",
            "0.9.54",
            "0.9.54-rc2",
            "0.9.54-rc1",
            "0.9.52",
            "0.9.50-rc1",
            "0.9.48",
            "0.9.46-rc1",
            "0.9.44",
            "0.9.44-rc1",
            "0.9.42",
            "0.9.42-rc2",
            "0.9.38",
            "0.9.42-rc1",
            "disable-globalcfg",
            "0.9.40",
            "0.9.40-rc1",
            "0.9.38-rc1",
            "0.9.36",
            "0.9.36-rc1",
            "0.9.34",
            "0.9.34-rc1",
            "0.9.32",
            "0.9.32-rc1",
            "0.9.30",
            "0.9.30-rc1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-26910.json"
          }
        }
      ],
      "modified": "2026-10-20T10:54:34.719462336Z",
      "provider": "osv",
      "references": [
        "https://github.com/netblue30/firejail/releases/tag/0.9.64.4",
        "https://lists.debian.org/debian-lts-announce/2021/02/msg00015.html",
        "https://security.gentoo.org/glsa/202105-19",
        "https://www.debian.org/security/2021/dsa-4849",
        "https://github.com/netblue30/firejail/commit/97d8a03cad19501f017587cc4e47d8418273834b",
        "https://unparalleled.eu/blog/2021/20210208-rigged-race-against-firejail-for-local-root/",
        "https://unparalleled.eu/publications/2021/advisory-unpar-2021-0.txt"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*",
              "cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "9.0"
                  },
                  {
                    "last_affected": "9.0"
                  },
                  {
                    "introduced": "10.0"
                  },
                  {
                    "last_affected": "10.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-26910",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 385637,
  "published_at": "2021-02-08T20:15:13.09+00:00"
}