CVE-2023-36810: PYSEC-2026-1837 - PyPDF2 quadratic runtime with malformed PDF missing xref marker

CVE-2023-36810 · Severity: low · CVSS 3.1 · Published 2026-07-07

PyPDF2 quadratic runtime with malformed PDF missing xref marker

Technologies: pypdf2 (PyPI). Vendors: PyPI.

Quick answers

Is CVE-2023-36810 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2023-36810 being exploited in the wild.
How severe is CVE-2023-36810?
Low severity, with a CVSS score of 3.1, published 7 July 2026.
Which products and versions are affected?
pypdf2 (PyPI) ECOSYSTEM:introduced=0,fixed=1.27.9.
Is there a fix for CVE-2023-36810?
Yes. pypdf2 (PyPI): upgrade to 1.27.9 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2023-36810?
Check whether you run pypdf2 (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • pypdf2 (PyPI): upgrade to 1.27.9 or later
    pip install "pypdf2>=1.27.9"

Affected products

  • pypdf2 (PyPI) ECOSYSTEM:introduced=0,fixed=1.27.9

Identifiers

  • CVE-2023-36810
  • GHSA-jrm6-h9cq-8gqw
  • PYSEC-2026-1837

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.