---
id: CVE-2026-96639
title: >-
  Pillow multi-frame loaders can reuse stale native image storage after mode
  transitions
summary: >-
  Pillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame
  loaders can retain an ImagingCore allocation created for a narrow frame mode
  while a later frame of the same dimensions changes the logical mode and
  decoder tiles …
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-125
  - CWE-787
vendor: python-pillow
product: Pillow
affected:
  - 'Pillow >= 11.0.0, < 13.0.0'
published: '2026-10-21'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T21:06:42.111Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-96639'
references:
  - url: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-v9pv-5gc8-w2m6
    label: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-v9pv-5gc8-w2m6
  - url: 'https://github.com/python-pillow/Pillow/pull/10105'
    label: 'https://github.com/python-pillow/Pillow/pull/10105'
  - url: >-
      https://github.com/python-pillow/Pillow/commit/78d97d994579aef81aafe123773d525f40f2522a
    label: >-
      https://github.com/python-pillow/Pillow/commit/78d97d994579aef81aafe123773d525f40f2522a
  - url: 'https://github.com/python-pillow/Pillow/releases/tag/13.0.0'
    label: 'https://github.com/python-pillow/Pillow/releases/tag/13.0.0'
tags:
  - cve.org
ingestedAt: '2026-10-21T22:18:33.756Z'
---

## Overview

Pillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame loaders can retain an ImagingCore allocation created for a narrow frame mode while a later frame of the same dimensions changes the logical mode and decoder tiles to wider RGB or CMYK data. ImageFile.load_prepare() reuses the stale native storage because _im is non-null without verifying that its mode and size still match. Crafted PSD, MPO, DCX, or MIC frame transitions can then write wider pixels into the narrow allocation, causing native out-of-bounds writes and crashes. The MPO path can also cause a native over-read and, in demonstrated runtime-specific profiles, command execution. This issue is fixed in version 13.0.0.

## Affected

- `Pillow >= 11.0.0, < 13.0.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.