---
id: CVE-2026-31826
aliases:
  - GHSA-hqmh-ppp3-xvm7
  - PYSEC-2026-3019
title: 'pypdf: manipulated stream length values can exhaust RAM'
summary: 'pypdf: manipulated stream length values can exhaust RAM'
severity: medium
vendor: pypdf
product: pypdf
ecosystem: pip
affected:
  - pypdf < 6.8.0
patched:
  - pypdf 6.8.0
published: '2026-03-11'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:50:39.503255117Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-hqmh-ppp3-xvm7'
references:
  - url: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-hqmh-ppp3-xvm7'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31826'
  - url: 'https://github.com/py-pdf/pypdf/pull/3675'
  - url: >-
      https://github.com/py-pdf/pypdf/commit/3c550b3196adeba1506a26e57c09c09fac75e9aa
  - url: 'https://github.com/py-pdf/pypdf'
  - url: 'https://github.com/py-pdf/pypdf/releases/tag/6.8.0'
tags:
  - osv
  - pip
epss: 0.00179
epssPercentile: 0.06657
ingestedAt: '2026-07-13T18:57:59.353Z'
---

## Overview

### Impact

An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing a content stream with a rather large `/Length` value, regardless of the actual data length inside the stream.

### Patches
This has been fixed in [pypdf==6.8.0](https://github.com/py-pdf/pypdf/releases/tag/6.8.0).

### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#3675](https://github.com/py-pdf/pypdf/pull/3675).

As far as we are aware, this mostly affects reading from buffers of unknown size, as returned by `open("file.pdf", mode="rb")` for example. Passing a file path or a `BytesIO` buffer to *pypdf* instead does not seem to trigger the vulnerability.

## Affected packages

- `pypdf < 6.8.0`

## Remediation

Upgrade to a patched release:

- `pypdf 6.8.0`