---
id: CVE-2026-27025
aliases:
  - GHSA-wgvp-vg3v-2xq3
  - PYSEC-2026-3024
title: >-
  pypdf has possible long runtimes/large memory usage for large /ToUnicode
  streams
summary: >-
  pypdf has possible long runtimes/large memory usage for large /ToUnicode
  streams
severity: medium
vendor: pypdf
product: pypdf
ecosystem: pip
affected:
  - pypdf < 6.7.1
patched:
  - pypdf 6.7.1
published: '2026-02-18'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:36.045929384Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-wgvp-vg3v-2xq3'
references:
  - url: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-wgvp-vg3v-2xq3'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-27025'
  - url: 'https://github.com/py-pdf/pypdf/pull/3646'
  - url: >-
      https://github.com/py-pdf/pypdf/commit/77d7b8d7cfbe8dd179858dfa42666f73fc6e57a2
  - url: 'https://github.com/py-pdf/pypdf'
  - url: 'https://github.com/py-pdf/pypdf/releases/tag/6.7.1'
tags:
  - osv
  - pip
epss: 0.00184
epssPercentile: 0.07105
ingestedAt: '2026-07-13T18:58:04.541Z'
---

## Overview

### Impact

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and large memory consumption. This requires parsing the `/ToUnicode` entry of a font with unusually large values, for example during text extraction.

### Patches

This has been fixed in [pypdf==6.7.1](https://github.com/py-pdf/pypdf/releases/tag/6.7.1).

### Workarounds

If you cannot upgrade yet, consider applying the changes from PR [#3646](https://github.com/py-pdf/pypdf/pull/3646).

## Affected packages

- `pypdf < 6.7.1`

## Remediation

Upgrade to a patched release:

- `pypdf 6.7.1`