---
id: CVE-2026-102998
title: pypdf is a free and open-source pure-python PDF library
summary: >-
  pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a
  crafted PDF with form field values can cause
  pypdf/generic/_appearance_stream.py appearance-stream generation to repeat
  invariant selection-data work inside a lo…
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'
cwe:
  - CWE-400
vendor: py-pdf
product: pypdf
affected:
  - pypdf < 6.19.0
published: '2026-09-30'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T21:17:07.177'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-102998'
references:
  - url: >-
      https://github.com/py-pdf/pypdf/commit/959467a9b95be83e2dc5ae873ece5f371263ede7
    label: security-advisories@github.com
  - url: 'https://github.com/py-pdf/pypdf/pull/4087'
    label: security-advisories@github.com
  - url: 'https://github.com/py-pdf/pypdf/releases/tag/6.19.0'
    label: security-advisories@github.com
  - url: 'https://github.com/py-pdf/pypdf/security/advisories/GHSA-php9-fj8v-98fj'
    label: security-advisories@github.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-30T20:49:24.715485Z'
cvssSource: cna
ingestedAt: '2026-09-30T21:25:07.839Z'
---

## Overview

pypdf is a free and open-source pure-python PDF library. Prior to 6.19.0, a crafted PDF with form field values can cause pypdf/generic/_appearance_stream.py appearance-stream generation to repeat invariant selection-data work inside a loop when an application updates fields with flattening enabled, resulting in excessive runtimes and application unavailability. This issue is fixed in version 6.19.0.

## Remediation

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