Pillow EpsImagePlugin negative %%BeginBinary byte count causes infinite loop denial of service

{
  "id": "434cba7ca801126303dc54ec14a0dfaff0b929720dded109354faad13e2e0131",
  "url": "https://osv.dev/vulnerability/CVE-2026-59203",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Pillow EpsImagePlugin negative %%BeginBinary byte count causes infinite loop denial of service",
    "summary": "Pillow is a Python imaging library. From 12.0.0 through 12.2.0, Pillow's EPS parser in PIL/EpsImagePlugin.py accepts a negative byte count in the %%BeginBinary directive, allowing a crafted EPS file to cause Image.open() to seek backwards to the same directive and parse it repeatedly in an infinite loop. This issue is fixed in version 12.3.0.",
    "evidence": "osv:CVE-2026-59203",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-59203",
      "aliases": [
        "BIT-pillow-2026-59203",
        "CVE-2026-59203",
        "GHSA-pg7v-jwj7-p798",
        "PYSEC-2026-3452"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/python-pillow/pillow",
              "type": "GIT",
              "events": [
                {
                  "introduced": "693df7b42c666f88c719f9973be0ad71607328e0"
                },
                {
                  "fixed": "bb1d8e8ab8d29048624d96e3ee53cecf7c13d13d"
                },
                {
                  "fixed": "03992618118b4a76b6163cd72ab5ecd684133b83"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "12.0.0"
                      },
                      {
                        "fixed": "12.3.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "03992618118b4a76b6163cd72ab5ecd684133b83"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "bb1d8e8ab8d29048624d96e3ee53cecf7c13d13d"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "12.3.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "12.2.0",
            "12.1.0",
            "12.0.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-59203.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:21.568663814Z",
      "provider": "osv",
      "references": [
        "https://github.com/python-pillow/Pillow/releases/tag/12.3.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59203.json",
        "https://github.com/python-pillow/Pillow/security/advisories/GHSA-pg7v-jwj7-p798",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-59203",
        "https://github.com/python-pillow/Pillow/commit/03992618118b4a76b6163cd72ab5ecd684133b83",
        "https://github.com/python-pillow/Pillow/pull/9708"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-835"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59203.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-59203",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 487824,
  "published_at": "2026-07-14T15:43:58.333+00:00"
}