CVE-2026-54651
Received Received - Intake
Infinite Loop in PyPDF Due to Malicious PDF Merge

Publication date: 2026-06-22

Last updated on: 2026-06-22

Assigner: GitHub, Inc.

Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.13.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. This vulnerability is fixed in 6.13.1.
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Meta Information
Published
2026-06-22
Last Modified
2026-06-22
Generated
2026-06-23
AI Q&A
2026-06-23
EPSS Evaluated
N/A
NVD
CVE-2026-54651
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
py-pdf pypdf 6.13.1
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-835 The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.
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Executive Summary

This vulnerability exists in the pypdf library, a pure-python PDF library. Before version 6.13.1, an attacker could craft a specially designed PDF file that, when merged with a file containing threads or articles into a writer, causes the process to enter an infinite loop.

This infinite loop can disrupt normal operations and is fixed in version 6.13.1 of pypdf.

Impact Analysis

The primary impact of this vulnerability is that it can cause an infinite loop during PDF processing when merging certain crafted PDF files. This can lead to denial of service by making the application or system using pypdf unresponsive or stuck.

Mitigation Strategies

To mitigate this vulnerability, you should upgrade the pypdf library to version 6.13.1 or later, where the issue has been fixed.

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