{"id":"CVE-2026-96640","summary":"Pillow PDF append accepts malformed shared page-tree DAG causing resource exhaustion","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.","aliases":["GHSA-mrfp-p49p-3hf2"],"modified":"2026-10-22T10:46:26.514769591Z","published":"2026-10-21T21:03:22.785Z","database_specific":{"unresolved_ranges":[{"extracted_events":[{"range":[{"introduced":"5.1.0"},{"fixed":"13.0.0"}],"source":"AFFECTED_FIELD","strategy":"StringRangeExpression"}]},{"extracted_events":[{"range":[{"fixed":"13.0.0"}],"source":"DESCRIPTION"}]}],"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"},"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"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python-pillow/pillow","events":[{"introduced":"0"},{"fixed":"6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7"},{"fixed":"293218ad059d994baf1777d882911bed6a49704a"}],"database_specific":{"extracted_events":[{"range":[{"fixed":"6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7"}],"source":"REFERENCES_COMMIT"},{"source":"REFERENCES_TAG","original_tag":"13.0.0","range":[{"fixed":"293218ad059d994baf1777d882911bed6a49704a"}]}]}}],"versions":["12.3.0","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-2026-96640.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","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"}]}