## Pillow: Decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS

- 種別: advisory
- 重大度: high
- 関連技術: python
- CVE: CVE-2026-96637
- 公開日時: 2026-10-22T15:57:17.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-g842-9rc4-69pw)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-g842-9rc4-69pw

影響: pip:pillow < 13.0.0 → 13.0.0
SpiderImagePlugin's seek() bypasses the decompression bomb check, allowing a tiny ( DecompressionBombWarning fires correctly. - BYPASS: Image.open(stack, frame0=1x1) passes; im.seek(1) sets size (100,100) with NO DecompressionBombWarning/Error -> the check is bypassed. Real-world impact: a large frame-1 nsam/nrow (e.g. 40000x40000) causes im.load() to allocate ~6.4 GB (mode F) with the bomb check fully bypassed, from a file under 1 KB. Suggested fix Call Image._decompression_bomb_check(self.siz…