{"id":"CVE-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":["GHSA-g842-9rc4-69pw"],"modified":"2026-10-22T11:21:13.083890972Z","published":"2026-10-21T21:01:20.249Z","database_specific":{"cwe_ids":["CWE-400","CWE-409"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96637.json","cna_assigner":"GitHub_M"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/96xxx/CVE-2026-96637.json"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/commit/7cb0e02389d8aac2a60896a490f572db0b07b841"},{"type":"FIX","url":"https://github.com/python-pillow/Pillow/pull/10076"},{"type":"WEB","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":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-96637"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/python-pillow/pillow","events":[{"introduced":"0"},{"fixed":"293218ad059d994baf1777d882911bed6a49704a"},{"fixed":"7cb0e02389d8aac2a60896a490f572db0b07b841"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"0"},{"fixed":"13.0.0"}],"source":"AFFECTED_FIELD","strategy":"StringRangeExpression"},{"source":"REFERENCES_COMMIT","range":[{"fixed":"7cb0e02389d8aac2a60896a490f572db0b07b841"}]},{"original_tag":"13.0.0","range":[{"fixed":"293218ad059d994baf1777d882911bed6a49704a"}],"source":"REFERENCES_TAG"}]}}],"versions":["12.3.0","12.2.0","12.1.0","12.0.0","11.3.0","11.2.1","11.1.0","11.0.0","10.4.0","10.3.0","10.2.0","10.1.0","10.0.0","9.5.0","9.4.0","9.3.0","9.2.0","9.1.0","9.0.0","8.4.0","8.3.0","8.2.0","8.1.0","8.0.0","7.2.0","7.1.0","7.0.0","6.2.0","6.1.0","6.0.0","5.4.0","5.3.0","5.2.0","5.1.0","5.0.0","4.3.0","4.2.0","4.1.0","4.0.0","4.0.0a","3.4.0","3.3.0","3.2.0","3.1.0","3.1.0-rc1","2.9.0","2.9.0.dev2","2.9.0.dev1","2.9.0.dev0","2.8.1","2.8.0","2.7.0","2.5.0","2.3.0","2.2.1","2.2.0","2.1.0","2.0.0","1.7.8","1.7.7","1.2","1.0"],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-96637.json"}}],"schema_version":"1.9.2","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"}]}