Pillow GdImageFile decompression bomb protection bypass

{
  "id": "c0cdc7ed1ddbcc81961cc1e67c8503058c72d161f9b2b1bb3e248f80aa435fab",
  "url": "https://osv.dev/vulnerability/CVE-2026-55380",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Pillow GdImageFile decompression bomb protection bypass",
    "summary": "Pillow is a Python imaging library. Prior to 12.3.0, PIL/GdImageFile.py GdImageFile._open() read image dimensions from the GD 2.x header and stored them in self._size without calling Image._decompression_bomb_check(), allowing a crafted .gd file to trigger excessive C-heap allocation when loaded. This issue is fixed in version 12.3.0.",
    "evidence": "osv:CVE-2026-55380",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-55380",
      "aliases": [
        "BIT-pillow-2026-55380",
        "CVE-2026-55380",
        "GHSA-phj9-mv4w-65pm",
        "PYSEC-2026-2256"
      ],
      "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": "bb1d8e8ab8d29048624d96e3ee53cecf7c13d13d"
                },
                {
                  "fixed": "f39b0ae6624eb2d7c5c5d651d9bb5fdbd96a8675"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "12.3.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "f39b0ae6624eb2d7c5c5d651d9bb5fdbd96a8675"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "12.2.0",
            "12.1.0",
            "12.0.0",
            "11.3.0",
            "11.2.1",
            "11.1.0",
            "11.0.0",
            "10.4.0",
            "10.3.0",
            "10.2.0",
            "10.1.0",
            "10.0.0",
            "9.5.0",
            "9.4.0",
            "9.3.0",
            "9.2.0",
            "9.1.0",
            "9.0.0",
            "8.4.0",
            "8.3.0",
            "8.2.0",
            "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-2026-55380.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:22.961053934Z",
      "provider": "osv",
      "references": [
        "https://github.com/python-pillow/Pillow/blob/main/docs/releasenotes/12.3.0.rst",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55380.json",
        "https://github.com/python-pillow/Pillow/security/advisories/GHSA-phj9-mv4w-65pm",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-55380",
        "https://github.com/python-pillow/Pillow/commit/f39b0ae6624eb2d7c5c5d651d9bb5fdbd96a8675"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-789"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55380.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-55380",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 489323,
  "published_at": "2026-07-06T18:50:14.789+00:00"
}