---
title: "CVE-2026-112398: Pillow: Heap buffer overflow in FlashPix (FPX) JPEG decoding leads to code execution"
url: https://erroneo.us/security/cve/CVE-2026-112398/
description: "CVE-2026-112398 (pillow (PyPI)): Pillow is a Python imaging library. Prior to 13.0.0, Pillow's FlashPix JPEG-tile decoder can write decoded scanlines beyond…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-10-19
date_modified: 2026-10-23
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-112398"
kev: false
cvss: 9.2
epss: 0.00321
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-112398: Pillow: Heap buffer overflow in FlashPix (FPX) JPEG decoding leads to code execution

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.3% , percentile 24: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 24% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes pillow (PyPI) <= 12.3.0, fixed in 13.0.0 . Check your lockfile, including transitive dependencies.

## What it is

Pillow is a Python imaging library. Prior to 13.0.0, Pillow's FlashPix JPEG-tile decoder can write decoded scanlines beyond the allocated tile buffer. FlashPix (FPX) JPEG decoding selects raw mode LA with two bytes per pixel, while an unrecognized JPEG mode can be decoded as JCSUNKNOWN with four components, causing ImagingJpegDecode to write four-component scanlines into the two-byte tile buffer. An attacker can supply a crafted OLE2 FlashPix file to an application with the optional olefile dependency installed that opens or thumbnails untrusted input. This can corrupt heap memory and may allow arbitrary code execution. This issue is fixed in version 13.0.0.

## Affected packages

- PyPI `pillow` <= 12.3.0 → fixed: 13.0.0

## Affected products (CVE record)

- python-pillow Pillow: < 13.0.0

## Severity

- GitHub_M CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-23): 0.32% probability of exploitation activity in the next 30 days; percentile 24.

## Sources

- [GitHub Advisory GHSA-5x8w-8jj5-q52h](https://github.com/advisories/GHSA-5x8w-8jj5-q52h)
- [CVE.org record CVE-2026-112398](https://www.cve.org/CVERecord?id=CVE-2026-112398)
- [NVD entry CVE-2026-112398](https://nvd.nist.gov/vuln/detail/CVE-2026-112398)
- [github.com](https://github.com/python-pillow/Pillow/security/advisories/GHSA-5x8w-8jj5-q52h)
- [github.com](https://github.com/python-pillow/Pillow/commit/242a059aedc1935097d9aa1dc3f099750467ba75)
- [github.com](https://github.com/python-pillow/Pillow/releases/tag/13.0.0)

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Source page: https://erroneo.us/security/cve/CVE-2026-112398/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt