Security advisory

{
  "id": "ef3e0d65f33999bbde3ce994e41aaa4ac8fbfdf3cdecc2c1311405cf2be4092d",
  "url": "https://osv.dev/vulnerability/CVE-2021-20254",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-20254",
    "summary": "A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.",
    "evidence": "osv:CVE-2021-20254",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-20254",
      "aliases": [
        "CVE-2021-20254"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/samba-team/samba",
              "type": "GIT",
              "events": [
                {
                  "introduced": "b1d9ddf738c6e59e489bc9c339ce6de5988b689e"
                },
                {
                  "fixed": "703c6301013f78e80882abfe8375d6a45a176b7f"
                },
                {
                  "introduced": "3fe82c204f0d88cb6db50b7bd1f798b591a918f8"
                },
                {
                  "fixed": "058aaad5f4a2399dc0c11b42a6650c251957f24d"
                },
                {
                  "introduced": "9b49519cae3e967af9ea48dc5fcfb6c145e31db4"
                },
                {
                  "fixed": "e29fc62e1d60a1add177fca059d0d67dcf6a1866"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "3.6.0"
                      },
                      {
                        "fixed": "4.12.15"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.13.0"
                      },
                      {
                        "fixed": "4.13.8"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "cpe": "cpe:2.3:a:samba:samba:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "4.14.0"
                      },
                      {
                        "fixed": "4.14.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "samba-4.13.7",
            "samba-4.14.3",
            "ldb-2.2.1",
            "samba-4.13.6",
            "samba-4.13.5",
            "samba-4.14.0",
            "samba-4.13.4",
            "samba-4.13.3",
            "samba-4.13.2",
            "samba-4.13.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-20254.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:34.855323471Z",
      "provider": "osv",
      "references": [
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/",
        "https://lists.debian.org/debian-lts-announce/2021/05/msg00023.html",
        "https://security.gentoo.org/glsa/202105-22",
        "https://security.netapp.com/advisory/ntap-20210430-0001/",
        "https://www.samba.org/samba/security/CVE-2021-20254.html",
        "https://bugzilla.redhat.com/show_bug.cgi?id=1949442"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "debian:debian_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "9.0"
                  },
                  {
                    "last_affected": "9.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          },
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "32"
                  },
                  {
                    "last_affected": "32"
                  },
                  {
                    "introduced": "33"
                  },
                  {
                    "last_affected": "33"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          },
          {
            "cpes": [
              "cpe:2.3:o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*",
              "cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*"
            ],
            "vendor_product": "redhat:enterprise_linux",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "7.0"
                  },
                  {
                    "last_affected": "7.0"
                  },
                  {
                    "introduced": "8.0"
                  },
                  {
                    "last_affected": "8.0"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-20254",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 433624,
  "published_at": "2021-05-05T14:15:07.883+00:00"
}