---
id: CVE-2026-113790
title: 'pypdf: Possible large memory usage when parsing arrays and dictionaries'
summary: >-
  pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an
  attacker can craft a PDF containing arrays or dictionaries with many elements,
  causing parsing to consume large amounts of memory. This issue is fixed in
  versio…
severity: medium
cvss: 6
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
cwe:
  - CWE-400
  - CWE-770
vendor: py-pdf
product: pypdf
affected:
  - pypdf < 6.21.0
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-10-28T01:18:48.608537Z'
published: '2026-10-21'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T01:18:59.036Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-113790'
references:
  - url: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-f54x-cmq8-qg57'
    label: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-f54x-cmq8-qg57'
  - url: 'https://github.com/py-pdf/pypdf/pull/4218'
    label: 'https://github.com/py-pdf/pypdf/pull/4218'
  - url: >-
      https://github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
    label: >-
      https://github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
  - url: 'https://github.com/py-pdf/pypdf/releases/tag/6.21.0'
    label: 'https://github.com/py-pdf/pypdf/releases/tag/6.21.0'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-113790'
  - url: 'https://github.com/py-pdf/pypdf'
  - url: 'https://github.com/advisories/GHSA-f54x-cmq8-qg57'
tags:
  - cve.org
  - osv
  - pip
  - ghsa
epss: 0.00392
epssPercentile: 0.33135
aliases:
  - GHSA-f54x-cmq8-qg57
ecosystem: pip
patched:
  - pypdf 6.21.0
ingestedAt: '2026-10-21T16:05:17.698Z'
---

## Overview

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF containing arrays or dictionaries with many elements, causing parsing to consume large amounts of memory. This issue is fixed in version 6.21.0.

## Affected

- `pypdf < 6.21.0`

## Remediation

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

## Package advisory (CVE-2026-113790)

Affected packages:

- `pypdf < 6.21.0`

Patched in:

- `pypdf 6.21.0`

Source: https://osv.dev/vulnerability/GHSA-f54x-cmq8-qg57