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

Summary When an application appends to an existing PDF with Image.save..., format="PDF", append=True, Pillow parses that file with PdfParser. Two recursive parsers have no effective bound. linearizepagetree follows /Kids with no visited set or depth limit, so a cyclic or duplicated page tree...

GHSA-P4WG-P73J-C528 Pillow: Unbounded recursion parsing a PDF page tree or trailer chain (incomplete fix for CVE-2026-42310)

Summary When an application appends to an existing PDF with Image.save..., format="PDF", append=True, Pillow parses that file with PdfParser. Two recursive parsers have no effective bound. linearizepagetree follows /Kids with no visited set or depth limit, so a cyclic or duplicated page tree...

CVE-2026-112391

The Pillow Python imaging library (versions 5.1.0 through 13.0.0) contains a vulnerability in PdfParser.get_value() and linearize_page_tree() . The parser fails to limit recursion depth when processing nested PDF objects, specifically when an existing PDF is opened for append. An attacker can pro...

CVE-2026-112391 Pillow: PdfParser can recurse without limit in get_value() and linearize_page_tree()

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow's PdfParser.getvalue can recurse without a limit while reading nested PDF objects. The parser follows attacker-controlled arrays and dictionaries when an existing PDF is opened for append. An attacker can provide a deeply nested...