CVE-2026-112391

Received Received - Intake

Denial of Service in Pillow via Recursive PDF Parsing

Publication date: 2026-10-19

Last updated on: 2026-10-19

Assigner: GitHub, Inc.

Description

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow's PdfParser.get_value() 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 PDF to an application that saves an image with PDF append enabled. This can raise an uncaught RecursionError or terminate the worker, causing denial of service. This issue is fixed in version 13.0.0.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-10-19

Last Modified

2026-10-19

Generated

2026-10-20

AI Q&A

2026-10-20

EPSS Evaluated

N/A

NVD

CVE-2026-112391

Affected Vendors & Products

Vendor	Product	Version / Range
python-pillow	Pillow	>= 5.1.0, < 13.0.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-835	The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

Attack-Flow Graph

Executive Summary

Pillow's PdfParser.get_value() function in versions 5.1.0 to 13.0.0 can enter infinite recursion when processing deeply nested PDF objects. This happens because the parser follows attacker-controlled nested arrays and dictionaries without a recursion limit. When an image is saved with PDF append enabled, a malicious PDF can trigger a RecursionError or crash the worker process, causing a denial of service.

Detection Guidance

This vulnerability can be detected by checking the version of Pillow installed on your system. Run 'pip show Pillow' or 'pip list' to verify if the version is below 13.0.0. If so, the system is vulnerable.

Impact Analysis

If you use Pillow to process PDFs with append mode enabled, an attacker could provide a specially crafted PDF file that causes your application to crash or become unresponsive. This could disrupt services relying on image processing, such as web applications handling user-uploaded PDFs.

Mitigation Strategies

Upgrade Pillow to version 13.0.0 or later immediately. Use 'pip install --upgrade Pillow' to apply the fix. Avoid opening or processing untrusted PDF files until the upgrade is complete.

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