{"schemaVersion":3,"id":"CVE-2026-96640","aliases":[],"status":"published","duplicateOf":null,"title":null,"description":"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.","dates":{"published":"2026-10-21T21:03:22.785Z","modified":"2026-10-21T21:03:22.785Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":8.2,"severity":"high","version":"4.0","versionLabel":"v4.0","source":"CVE.org","vector":"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","computed":false,"selection":"backend-summary"},"metrics":[{"version":"4.0","versionLabel":"v4.0","source":"CVE.org","score":8.2,"severity":"high","vector":"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","exploitability":null,"impact":null,"computed":false},{"version":"4.0","versionLabel":"v4.0","source":"NVD","score":8.2,"severity":"high","vector":"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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","exploitability":null,"impact":null,"computed":false}]},"epss":{"probability":null,"percentile":null,"severity":"unknown","asOf":null,"change":{"pp":null,"baselineDate":null,"baselineScore":null},"history":[],"last30":[]},"kev":{"state":"not-listed","entries":[],"listedCount":0,"totalCatalogs":3,"catalogs":[{"source":"cisa","label":"CISA","listed":false,"entry":null},{"source":"enisa","label":"ENISA","listed":false,"entry":null},{"source":"circl","label":"CIRCL","listed":false,"entry":null}]},"ransomware":{"state":"none-recorded","sources":[]},"exploits":[],"exploitCount":0,"weaknesses":[{"id":"CWE-400","name":"Uncontrolled Resource Consumption","description":"The product does not properly control the allocation and maintenance of a limited resource.","type":"weakness","status":"Draft","abstraction":"Class","likelihoodOfExploit":"High","url":"https://cwe.mitre.org/data/definitions/400.html"},{"id":"CWE-407","name":"Inefficient Algorithmic Complexity","description":"An algorithm in a product has an inefficient worst-case computational complexity that may be detrimental to system performance and can be triggered by an attacker, typically using crafted manipulations that ensure that the worst case is being reached.","type":"weakness","status":"Incomplete","abstraction":"Class","likelihoodOfExploit":"Low","url":"https://cwe.mitre.org/data/definitions/407.html"}],"affected":[{"vendor":"python-pillow","product":"pillow","name":"Pillow","label":"pillow","ecosystem":null,"cpePart":"a","purl":null,"purlType":null,"versions":[{"text":"≥ 5.1.0, < 13.0.0","noFixRecorded":false,"fixedIn":null}],"versionsText":"≥ 5.1.0, < 13.0.0","eol":null,"hubHref":"/vendor/python-pillow/pillow"}],"affectedCount":1,"eol":{"hasEol":false,"count":0},"references":[{"url":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-mrfp-p49p-3hf2","label":"github.com/python-pillow/Pillow/security/advisories/GHSA-mrfp-p49p-3hf2","hostname":"github.com","tags":["X Refsource CONFIRM"]},{"url":"https://github.com/python-pillow/Pillow/pull/10093","label":"github.com/python-pillow/Pillow/pull/10093","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/python-pillow/Pillow/commit/6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7","label":"github.com/python-pillow/Pillow/commit/6f0e7ee1f9c2fe227906f8a4b926e6622b702bc7","hostname":"github.com","tags":["X Refsource MISC"]},{"url":"https://github.com/python-pillow/Pillow/releases/tag/13.0.0","label":"github.com/python-pillow/Pillow/releases/tag/13.0.0","hostname":"github.com","tags":["X Refsource MISC"]}],"lineage":{"upstream":[],"downstream":[],"duplicates":[],"related":[]},"timeline":[{"kind":"published","date":"2026-10-21T21:03:22.785Z","label":"Published","detail":"Vulnerability first disclosed.","source":null}],"risk":{"score":33,"level":"medium","profile":"Default","thresholds":{"critical":75,"high":50,"medium":25,"low":10}},"meta":{"dataAsOf":"2026-10-22T10:00:29.142Z","stale":false,"partial":false}}