{"id":"BIT-pillow-2026-96637","summary":"Pillow: Decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS","details":"Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.","aliases":["CVE-2026-96637","GHSA-g842-9rc4-69pw","PYSEC-2026-4338"],"modified":"2026-10-29T10:55:56.102454725Z","published":"2026-10-29T08:58:11.573Z","database_specific":{"cpes":["cpe:2.3:a:python:pillow:*:*:*:*:*:python:*:*"],"severity":"High"},"references":[{"type":"FIX","url":"https://github.com/python-pillow/Pillow/commit/7cb0e02389d8aac2a60896a490f572db0b07b841"},{"type":"REPORT","url":"https://github.com/python-pillow/Pillow/pull/10076"},{"type":"ARTICLE","url":"https://github.com/python-pillow/Pillow/releases/tag/13.0.0"},{"type":"ADVISORY","url":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-g842-9rc4-69pw"},{"type":"WEB","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-96637"}],"affected":[{"package":{"name":"pillow","ecosystem":"Bitnami","purl":"pkg:bitnami/pillow"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"13.0.0"}]}],"database_specific":{"source":"https://github.com/bitnami/vulndb/tree/main/data/pillow/BIT-pillow-2026-96637.json"},"severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/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"}]}],"schema_version":"1.9.2"}