---
id: CVE-2026-112894
title: 'Pillow: Quadratic-time DoS in PDF save_all (PdfParser.next_object_id)'
summary: >-
  Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow takes
  quadratic time to reserve PDF object identifiers when saving many frames with
  save_all enabled. PdfParser.next_object_id() repeatedly rebuilds and scans all
  previo…
severity: high
cvss: 8.7
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-407
vendor: python-pillow
product: Pillow
affected:
  - 'Pillow >= 5.1.0, < 13.0.0'
published: '2026-10-19'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T21:55:19.424Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-112894'
references:
  - url: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-jg86-v3jv-hrpm
    label: >-
      https://github.com/python-pillow/Pillow/security/advisories/GHSA-jg86-v3jv-hrpm
  - url: >-
      https://github.com/python-pillow/Pillow/commit/f6a852555f1a1bdff7781abf25f1a3b8bd6ce6cb
    label: >-
      https://github.com/python-pillow/Pillow/commit/f6a852555f1a1bdff7781abf25f1a3b8bd6ce6cb
  - 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: '2026-10-19T22:46:42.329Z'
---

## Overview

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow takes quadratic time to reserve PDF object identifiers when saving many frames with save_all enabled. PdfParser.next_object_id() repeatedly rebuilds and scans all previously reserved identifiers for every object. An attacker can supply a multi-frame image, including a small APNG with a large declared frame count, to an application that converts it to a multipage PDF. This can consume excessive CPU and deny service. This issue is fixed in version 13.0.0.

## Affected

- `Pillow >= 5.1.0, < 13.0.0`

## Remediation

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