{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "range": [
                  {
                    "introduced": "5.1.0"
                  },
                  {
                    "fixed": "13.0.0"
                  }
                ],
                "source": "AFFECTED_FIELD",
                "strategy": "StringRangeExpression"
              },
              {
                "range": [
                  {
                    "fixed": "6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7"
                  }
                ],
                "source": "REFERENCES_COMMIT"
              },
              {
                "original_tag": "13.0.0",
                "range": [
                  {
                    "fixed": "293218ad059d994baf1777d882911bed6a49704a"
                  }
                ],
                "source": "REFERENCES_TAG"
              }
            ]
          },
          "events": [
            {
              "introduced": "fda33d5c09142c4bb0e99964919d01c2cc5f5995"
            },
            {
              "fixed": "293218ad059d994baf1777d882911bed6a49704a"
            },
            {
              "fixed": "6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7"
            }
          ],
          "repo": "https://github.com/python-pillow/pillow",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-mrfp-p49p-3hf2"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-400",
      "CWE-407"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96640.json"
  },
  "details": "Pillow is a Python imaging library. From 5.1.0 until 13.0.0, PdfParser.linearize_page_tree() in src/PIL/PdfParser.py treats a PDF /Pages graph as a tree without tracking duplicate indirect references. When Image.save(..., format=\"PDF\", append=True) processes an attacker-controlled existing PDF whose /Kids arrays repeatedly reference the same child /Pages node, Pillow expands the shared subtree as distinct pages. A compact malformed PDF can therefore create exponentially many page references and consume disproportionate CPU before the append completes. This issue is fixed in version 13.0.0.",
  "id": "CVE-2026-96640",
  "modified": "2026-10-23T02:30:56.078934143Z",
  "published": "2026-10-21T21:03:22.785Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96640.json"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python-pillow/Pillow/commit/6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7"
    },
    {
      "type": "FIX",
      "url": "https://github.com/python-pillow/Pillow/pull/10093"
    },
    {
      "type": "WEB",
      "url": "https://github.com/python-pillow/Pillow/releases/tag/13.0.0"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/python-pillow/Pillow/security/advisories/GHSA-mrfp-p49p-3hf2"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-96640"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Pillow PDF append accepts malformed shared page-tree DAG causing resource exhaustion"
}