CVE-2026-112399

Received Received - Intake

Memory Exhaustion in Pillow via APNG Handling

Publication date: 2026-10-19

Last updated on: 2026-10-19

Assigner: GitHub, Inc.

Description

Pillow is a Python imaging library. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.

CVSS Scores

EPSS Scores

Probability:
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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-2026-112399

Affected Vendors & Products

Vendor	Product	Version / Range
python-pillow	Pillow	>= 8.1.0, < 13.0.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-789	The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.

Attack-Flow Graph

Executive Summary

Pillow is a Python imaging library. From versions 8.1.0 to 13.0.0, it can allocate memory for an APNG disposal background at the full canvas size before checking for decompression bombs. A crafted APNG file with a small first frame, a very large declared canvas, and specific disposal settings can cause Pillow to allocate excessive memory during Image.open(), leading to denial of service.

Detection Guidance

This vulnerability can be detected by checking the installed version of Pillow. Run 'pip show Pillow' or 'python -c "import PIL; print(PIL.__version__)"' to verify if the version is below 13.0.0. If so, the system is vulnerable.

Impact Analysis

This vulnerability can cause your application to run out of memory and crash when processing a specially crafted APNG file. It affects systems using Pillow versions between 8.1.0 and 13.0.0, potentially disrupting services that rely on image processing.

Mitigation Strategies

Upgrade Pillow to version 13.0.0 or later immediately. Use 'pip install --upgrade Pillow' or update via your package manager. Avoid processing untrusted APNG files until the upgrade is complete.

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