BIT-PILLOW-2026-112895 Pillow: Unbounded recursion parsing a PDF page tree or trailer chain (incomplete fix for CVE-2026-42310)

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow can exhaust resources while parsing an existing PDF during an append operation. PdfParser follows page-tree child references without cycle or duplication tracking and follows previous-trailer chains with only an exact...