---
id: CVE-2026-112393
title: 'Pillow: Heap buffer overflow in _tiffWriteProc when saving TIFF to BytesIO'
summary: >-
  Pillow is a Python imaging library. From 2.0.0 until 13.0.0, Pillow has a heap
  buffer overflow and stale-heap disclosure in _tiffWriteProc when saving
  compressed TIFF data through libtiff to a target without a usable fileno(),
  such as By…
severity: critical
cvss: 9.2
cvssVector: 'CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-122
vendor: python-pillow
product: Pillow
affected:
  - 'Pillow >= 2.0.0, < 13.0.0'
ssvc:
  exploitation: poc
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-19T21:17:12.786867Z'
exploitAvailable: true
published: '2026-10-19'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T21:17:41.571Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112393'
references:
  - url: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-332p-7hrc-92wf
    label: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-332p-7hrc-92wf
  - url: >-
      https://github.com/python-pillow/Pillow/commit/11582e5ffbdceb973d5ee593f3105af5a9852b40
    label: >-
      https://github.com/python-pillow/Pillow/commit/11582e5ffbdceb973d5ee593f3105af5a9852b40
  - 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
  - exploit-available
ingestedAt: '2026-10-19T21:43:56.127Z'
---

## Overview

Pillow is a Python imaging library. From 2.0.0 until 13.0.0, Pillow has a heap buffer overflow and stale-heap disclosure in _tiffWriteProc when saving compressed TIFF data through libtiff to a target without a usable fileno(), such as BytesIO. The callback sizes its allocation from the prior buffer size instead of the current write position, allowing an attacker-controlled out-of-line TIFF tag or retained ICC profile to be copied beyond the allocation after libtiff seeks forward. This overflow can crash the process and may allow code execution. Independently, unwritten alignment gaps in compressed TIFF output larger than 64 KiB can disclose stale heap bytes without a crafted tag. File paths and targets with real file descriptors are unaffected. This issue is fixed in version 13.0.0.

## Affected

- `Pillow >= 2.0.0, < 13.0.0`

## Remediation

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