{"id":"PYSEC-2026-4342","details":"Pillow is a Python imaging library. From 11.0.0 until 13.0.0, Exif.load() in src/PIL/Image.py repeatedly slices the remaining EXIF data while it begins with the six-byte Exif header. src/PIL/PngImagePlugin.py accepts an uncapped PNG eXIf chunk, so a file filled with repeated headers causes a new shrinking copy on every iteration and quadratic CPU work. The condition is reachable through Image.getexif(), Image._getexif(), and ImageOps.exif_transpose(), including common photo-upload rotation workflows. This issue is fixed in version 13.0.0.","aliases":["CVE-2026-96643","GHSA-g4qv-2jxx-769h"],"modified":"2026-10-28T11:00:02.992659382Z","published":"2026-10-21T21:20:32.797Z","references":[{"type":"ADVISORY","url":"https://github.com/python-pillow/Pillow/releases/tag/13.0.0"},{"type":"ADVISORY","url":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-g4qv-2jxx-769h"},{"type":"REPORT","url":"https://github.com/python-pillow/Pillow/pull/10073"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/commit/806e38381c781f32bbd22f4cd026678acd40fd6c"}],"affected":[{"package":{"name":"pillow","ecosystem":"PyPI","purl":"pkg:pypi/pillow"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"11.0.0"},{"fixed":"13.0.0"}]}],"versions":["11.0.0","11.1.0","11.2.1","11.3.0","12.0.0","12.1.0","12.1.1","12.2.0","12.3.0"],"ecosystem_specific":{},"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pillow/PYSEC-2026-4342.yaml"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"}]}