## Pillow PDF append accepts malformed shared page-tree DAG causing resource exhaustion

- 種別: advisory
- 重大度: high
- 関連技術: python
- CVE: CVE-2026-96640
- 公開日時: 2026-10-22T16:00:47.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-mrfp-p49p-3hf2)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-mrfp-p49p-3hf2

影響: pip:Pillow >= 5.1.0, < 13.0.0 → 13.0.0
Pillow's documented PDF append path can spend disproportionate CPU time on a compact malformed PDF page tree. An attacker who can supply an existing PDF to an application that appends an image with Image.save(..., format="PDF", append=True) can provide a malformed /Pages tree where each level repeats the same child /Pages reference in /Kids. Pillow treats the graph as a tree and expands each repeated reference in PdfParser.linearize_page_tree() without tracking visited or duplicate indirect ref…