{"id":"CVE-2026-59197","aliases":["BIT-pillow-2026-59197","GHSA-xj96-63gp-2gmr","PYSEC-2026-3454"],"url":"https://o3.security/vulnerability/CVE-2026-59197","summary":"Pillow: Heap out-of-bounds write in Pillow `ImageFilter.RankFilter` via integer overflow in `ImagingExpand`","details":"Pillow is a Python imaging library. Prior to 12.3.0, Pillow's public rank-filter API can trigger a native heap out-of-bounds write when given a very large odd filter size because ImageFilter.RankFilter.filter() calls image.expand(size // 2, size // 2) before rank-filter size validation and ImagingExpand() computes output dimensions with unchecked signed int arithmetic. This issue is fixed in version 12.3.0.","published":"2026-07-14T16:25:23.520Z","modified":"2026-08-27T18:26:15.257129528Z","cvss":{"score":8.2,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"pillow","fixedVersion":"12.3.0"}],"fix":{"url":"https://github.com/python-pillow/Pillow/commit/cce3bdb867c77a3420261ed1bfdb6b0787ec8fc1","label":"python-pillow/Pillow@cce3bdb"},"references":[{"type":"WEB","url":"https://github.com/python-pillow/Pillow/releases/tag/12.3.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59197.json"},{"type":"ADVISORY","url":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-xj96-63gp-2gmr"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59197"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/commit/cce3bdb867c77a3420261ed1bfdb6b0787ec8fc1"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/pull/9695"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-08-27T18:26:15.257129528Z"}}