Pillow: Heap buffer overflow in FlashPix (FPX) JPEG decoding leads to code execution

pillow (pip)

Researcher: Alex Bouffard (mixbo@pebwalker.com) A heap buffer overflow in Pillow's FlashPix (FPX) JPEG-tile decoder lets an attacker achieve arbitrary code execution by getting an application to open a single crafted file with Image.open().

Do this now

Upgrade Pillow to 13.0.0 now and avoid opening untrusted files with Image.open() until then.

Fix itpip install --upgrade "pillow>=13.0.0"

First seen: 23 Oct 2026
Last update: 23 Oct 2026, 21:55 UTC
Fixed in: pillow 13.0.0
Identifiers: CVE-2026-112398
Source: GitHub advisory
On the menu as: Python
PyPI packages

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Pillow: Heap buffer overflow in FlashPix (FPX) JPEG decoding leads to code execution
Severity: critical. Patch status: patched.
Affected: pillow (pip)
Fixed in: pillow 13.0.0
Ids: CVE-2026-112398

Researcher: Alex Bouffard (mixbo@pebwalker.com) A heap buffer overflow in Pillow's FlashPix (FPX) JPEG-tile decoder lets an attacker achieve arbitrary code execution by getting an application to open a single crafted file with Image.open().

## Steps
1. Search every lockfile and manifest (package-lock.json, yarn.lock, pnpm-lock.yaml, requirements*.txt, poetry.lock, uv.lock, composer.lock, go.sum, Cargo.lock, Gemfile.lock) for `pillow`. For each hit, compare the installed version with the fix on the same major line: pillow 13.0.0. If it's lower, give the exact upgrade command for the package manager this repo uses.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-112398") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://github.com/advisories/GHSA-5x8w-8jj5-q52h 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/security/advisories/GHSA-5x8w-8jj5-q52h https://nvd.nist.gov/vuln/detail/CVE-2026-112398
https://pwned.coffee/i/pillow-heap-buffer-overflow-in-flashpix-fpx-jpeg-decodin-cve-2026-112398

Sources

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