{"id":"PYSEC-2026-4341","details":"Pillow is a Python imaging library. Prior to 13.0.0, the TarIO initializer in src/PIL/TarIO.py accepts a negative octal member size and computes a backward seek that returns to the same 512-byte header. When the requested member name does not match, the parser repeatedly reads that header, consumes a full CPU core, and never returns. TarIO is reached only when an application directly uses PIL.TarIO.TarIO rather than the default Image.open() path. This issue is fixed in version 13.0.0.","aliases":["CVE-2026-96642","GHSA-3j72-p6qg-6xp7"],"modified":"2026-10-28T11:00:02.995829644Z","published":"2026-10-21T21:20:32.650Z","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-3j72-p6qg-6xp7"},{"type":"REPORT","url":"https://github.com/python-pillow/Pillow/pull/10012"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/commit/19b695fdcc5eddc37374e2b1645fc4185edaf71d"}],"affected":[{"package":{"name":"pillow","ecosystem":"PyPI","purl":"pkg:pypi/pillow"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"13.0.0"}]}],"versions":["1.0","1.1","1.2","1.3","1.4","1.5","1.6","1.7.0","1.7.1","1.7.2","1.7.3","1.7.4","1.7.5","1.7.6","1.7.7","1.7.8","10.0.0","10.0.1","10.1.0","10.2.0","10.3.0","10.4.0","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","2.0.0","2.1.0","2.2.0","2.2.1","2.2.2","2.3.0","2.3.1","2.3.2","2.4.0","2.5.0","2.5.1","2.5.2","2.5.3","2.6.0","2.6.1","2.6.2","2.7.0","2.8.0","2.8.1","2.8.2","2.9.0","3.0.0","3.1.0","3.1.0.rc1","3.1.0rc1","3.1.1","3.1.2","3.2.0","3.3.0","3.3.1","3.3.2","3.3.3","3.4.0","3.4.1","3.4.2","4.0.0","4.1.0","4.1.1","4.2.0","4.2.1","4.3.0","5.0.0","5.1.0","5.2.0","5.3.0","5.4.0","5.4.0.dev0","5.4.1","6.0.0","6.1.0","6.2.0","6.2.1","6.2.2","7.0.0","7.1.0","7.1.1","7.1.2","7.2.0","8.0.0","8.0.1","8.1.0","8.1.1","8.1.2","8.2.0","8.3.0","8.3.1","8.3.2","8.4.0","9.0.0","9.0.1","9.1.0","9.1.1","9.2.0","9.3.0","9.4.0","9.5.0"],"ecosystem_specific":{},"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/pillow/PYSEC-2026-4341.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"}]}