# CVE-2026-112398: Pillow FlashPix JPEG-tile decoder heap overflow

Source: https://junglewise.ai/threats/cve-2026-112398-pillow-is-a-python-imaging-library-prior-to-13-0-0-pillow-s  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-19. Updated: 2026-10-19  
License: CC BY 4.0 with a link back

CVE-2026-112398 · Severity: critical · CVSS 4 · Published 2026-10-19

Pillow is a widely-used Python library for opening, manipulating, and saving image files. The FlashPix image format decoder in Pillow prior to version 13.0.0 contains a heap buffer overflow that can occur when processing specially crafted image files. An attacker can exploit this by providing a malicious FlashPix file to an application that uses Pillow to open or generate thumbnails, potentially leading to data corruption, application crashes, or arbitrary code execution.

Technologies: [pillow (PyPI)](https://junglewise.ai/threats/technologies/pillow), [Python Pillow Pillow](https://junglewise.ai/threats/technologies/python-pillow-pillow). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi), [Python Pillow](https://junglewise.ai/threats/vendors/python-pillow).

## Quick answers

**Is CVE-2026-112398 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-112398 being exploited in the wild.

**How severe is CVE-2026-112398?** Critical severity, with a CVSS score of 4, published 19 October 2026.

**Which products and versions are affected?** pillow (PyPI) <= 12.3.0, ECOSYSTEM:introduced=0,fixed=13.0.0; Python Pillow Pillow before 13.0.0.

**Is there a fix for CVE-2026-112398?** Yes. pillow (PyPI): upgrade to 13.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-112398 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-112398?** Check whether you run pillow (PyPI) or Python Pillow Pillow at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- pillow (PyPI): upgrade to 13.0.0 or later

  ```sh
  pip install "pillow>=13.0.0"
  ```


## Technical details

The vulnerability exists in Pillow's FlashPix JPEG-tile decoder, where the decoder selects raw mode LA (two bytes per pixel) but can process an unrecognized JPEG mode as JCS_UNKNOWN with four components. This causes ImagingJpegDecode to write four-byte scanlines into a two-byte tile buffer, resulting in a heap buffer overflow. The attack requires an OLE2 FlashPix file and the optional olefile dependency to be installed; exploitation occurs when an untrusted image is opened or a thumbnail is generated.

## Affected products

- python-pillow Pillow before 13.0.0

## Identifiers

- CVE-2026-112398
- BIT-PILLOW-2026-112398
- GHSA-5x8w-8jj5-q52h
- PYSEC-2026-4330

## Timeline

- 2026-10-19: disclosed
- 2026-10-16: patched: Fix released in version 13.0.0

## References

- [https://github.com/python-pillow/Pillow/commit/242a059aedc1935097d9aa1dc3f099750467ba75](https://github.com/python-pillow/Pillow/commit/242a059aedc1935097d9aa1dc3f099750467ba75)
- [https://github.com/python-pillow/Pillow/releases/tag/13.0.0](https://github.com/python-pillow/Pillow/releases/tag/13.0.0)

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