---
id: CVE-2026-115580
aliases:
  - GHSA-gmh7-3g9r-mjh5
title: 'pypdf: Possible long runtimes for large xref table header limits'
summary: 'pypdf: Possible long runtimes for large xref table header limits'
severity: high
cvss: 7.1
cwe:
  - CWE-834
vendor: pypdf
product: pypdf
ecosystem: pip
affected:
  - pypdf < 6.21.2
patched:
  - pypdf 6.21.2
published: '2026-10-23'
updated: '2026-10-23'
sourceUpdated: '2026-10-23T20:54:14Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-gmh7-3g9r-mjh5'
references:
  - url: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-gmh7-3g9r-mjh5'
  - url: 'https://github.com/py-pdf/pypdf/pull/4239'
  - url: >-
      https://github.com/py-pdf/pypdf/commit/a3061e34b169d34478d520f5f049c53cfb1482b2
  - url: 'https://github.com/py-pdf/pypdf/releases/tag/6.21.2'
  - url: 'https://github.com/advisories/GHSA-gmh7-3g9r-mjh5'
tags:
  - ghsa
  - pip
  - cve.org
cvssVector: 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N'
cvssSource: cna
ingestedAt: '2026-10-23T20:36:51.540Z'
---

## Overview

### Impact

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires opening a file with large/wrong upper limits in the xref table.

### Patches

This has been fixed in [pypdf==6.21.2](https://github.com/py-pdf/pypdf/releases/tag/6.21.2).

### Workarounds

If you cannot upgrade yet, consider applying the changes from PR [#4239](https://github.com/py-pdf/pypdf/pull/4239).

## Affected packages

- `pypdf < 6.21.2`

## Remediation

Upgrade to a patched release:

- `pypdf 6.21.2`