CVE WatchOct 21, 2026

CVE-2026-96640

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, PdfParser.linearize_page_tree() in src/PIL/PdfParser.py treats a PDF /Pages gra

CVSS

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No CVSS

EPSS

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KEV

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Exploit Today

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0-100

Published: Oct 21, 2026 · Last modified: Oct 21, 2026 · CWE-400 · CWE-407

EPSS · 30d

Not enough EPSS history yet.

Technical description

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, PdfParser.linearize_page_tree() in src/PIL/PdfParser.py treats a PDF /Pages graph as a tree without tracking duplicate indirect references. When Image.save(..., format="PDF", append=True) processes an attacker-controlled existing PDF whose /Kids arrays repeatedly reference the same child /Pages node, Pillow expands the shared subtree as distinct pages. A compact malformed PDF can therefore create exponentially many page references and consume disproportionate CPU before the append completes. This issue is fixed in version 13.0.0.

Official references

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