Security advisory

{
  "id": "856f27a8d3c22c60e906360b90d52234521c2069d7f7dea226aac785016a9080",
  "url": "https://osv.dev/vulnerability/CVE-2021-27923",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-27923",
    "summary": "Pillow before 8.1.2 allows attackers to cause a denial of service (memory consumption) because the reported size of a contained image is not properly checked for an ICO container, and thus an attempted memory allocation can be very large.",
    "evidence": "osv:CVE-2021-27923",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-27923",
      "aliases": [
        "BIT-pillow-2021-27923",
        "CVE-2021-27923",
        "GHSA-95q3-8gr9-gm8w",
        "PYSEC-2021-42"
      ],
      "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": "741d8744a54bedbc49f16922c61a06fcb3681f53"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "8.1.1"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "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-2021-27923.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:26.918033083Z",
      "provider": "osv",
      "references": [
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/",
        "https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/S7G44Z33J4BNI2DPDROHWGVG2U7ZH5JU/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/TQQY6472RX4J2SUJENWDZAWKTJJGP2ML/",
        "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/ZTSY25UJU7NJUFHH3HWT575LT4TDFWBZ/",
        "https://pillow.readthedocs.io/en/stable/releasenotes/8.1.2.html",
        "https://pillow.readthedocs.io/en/stable/releasenotes/8.1.1.html",
        "https://security.gentoo.org/glsa/202107-33"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*",
              "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*"
            ],
            "vendor_product": "fedoraproject:fedora",
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "32"
                  },
                  {
                    "last_affected": "32"
                  },
                  {
                    "introduced": "33"
                  },
                  {
                    "last_affected": "33"
                  },
                  {
                    "introduced": "34"
                  },
                  {
                    "last_affected": "34"
                  }
                ],
                "source": "CPE_STRING"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-27923",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 431710,
  "published_at": "2021-03-03T09:15:14.327+00:00"
}