Security advisory

{
  "id": "56dff69347fb5eab338d0f371330904d28529c8180d9aa2d18525926db415766",
  "url": "https://osv.dev/vulnerability/CVE-2021-28676",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-28676",
    "summary": "An issue was discovered in Pillow before 8.2.0. For FLI data, FliDecode did not properly check that the block advance was non-zero, potentially leading to an infinite loop on load.",
    "evidence": "osv:CVE-2021-28676",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-28676",
      "aliases": [
        "BIT-pillow-2021-28676",
        "CVE-2021-28676",
        "GHSA-7r7m-5h27-29hp",
        "PYSEC-2021-92"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/python-pillow/pillow",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "e0e353c0ef7516979a9aedce3792596649ce4433"
                },
                {
                  "fixed": "bb6c11fb889e6c11b0ee122b828132ee763b5856"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "8.2.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "bb6c11fb889e6c11b0ee122b828132ee763b5856"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "8.1.0",
            "8.0.0",
            "7.2.0",
            "7.1.0",
            "7.0.0",
            "6.2.0",
            "6.1.0",
            "6.0.0",
            "5.4.0",
            "5.3.0",
            "5.2.0",
            "5.1.0",
            "5.0.0",
            "4.3.0",
            "4.2.0",
            "4.1.0",
            "4.0.0",
            "4.0.0a",
            "3.4.0",
            "3.3.0",
            "3.2.0",
            "3.1.0",
            "3.1.0-rc1",
            "2.9.0",
            "2.9.0.dev2",
            "2.9.0.dev1",
            "2.9.0.dev0",
            "2.8.1",
            "2.8.0",
            "2.7.0",
            "2.5.0",
            "2.3.0",
            "2.2.1",
            "2.2.0",
            "2.1.0",
            "2.0.0",
            "1.7.8",
            "1.7.7",
            "1.2",
            "1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-28676.json",
            "vanir_signatures": [
              {
                "id": "CVE-2021-28676-0f8c3b10",
                "digest": {
                  "threshold": 0.9,
                  "line_hashes": [
                    "276082854084581862752233006547183163125",
                    "154487951280376738261317199800104056040",
                    "196791183223561229908953348714930460735",
                    "108716279980050847017816890668636521998"
                  ]
                },
                "source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856",
                "target": {
                  "file": "src/libImaging/FliDecode.c"
                },
                "deprecated": false,
                "signature_type": "Line",
                "signature_version": "v1"
              },
              {
                "id": "CVE-2021-28676-89bdf835",
                "digest": {
                  "length": 3966,
                  "function_hash": "90249710371010666261709649153104395496"
                },
                "source": "https://github.com/python-pillow/pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856",
                "target": {
                  "file": "src/libImaging/FliDecode.c",
                  "function": "ImagingFliDecode"
                },
                "deprecated": false,
                "signature_type": "Function",
                "signature_version": "v1"
              }
            ],
            "vanir_signatures_modified": "2026-10-20T14:03:42Z"
          }
        }
      ],
      "modified": "2026-10-20T14:03:42.636551318Z",
      "provider": "osv",
      "references": [
        "https://github.com/python-pillow/Pillow/pull/5377",
        "https://lists.debian.org/debian-lts-announce/2021/07/msg00018.html",
        "https://pillow.readthedocs.io/en/stable/releasenotes/8.2.0.html#cve-2021-28676-fix-fli-dos",
        "https://security.gentoo.org/glsa/202107-33",
        "https://github.com/python-pillow/Pillow/commit/bb6c11fb889e6c11b0ee122b828132ee763b5856",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MQHA5HAIBOYI3R6HDWCLAGFTIQP767FL/"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "33"
                  },
                  {
                    "last_affected": "33"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-28676",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 388527,
  "published_at": "2021-06-02T16:15:08.797+00:00"
}