CVE-2025-66019
Unknown Unknown - Not Provided
BaseFortify

Publication date: 2025-11-26

Last updated on: 2025-11-26

Assigner: GitHub, Inc.

Description
pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
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Meta Information
Published
2025-11-26
Last Modified
2025-11-26
Generated
2026-06-16
AI Q&A
2025-11-26
EPSS Evaluated
2026-06-15
NVD
CVE-2025-66019
Affected Vendors & Products
Showing 1 associated CPE
Vendor Product Version / Range
pypdf pypdf 6.4.0
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-400 The product does not properly control the allocation and maintenance of a limited resource.
CWE-409 The product does not handle or incorrectly handles a compressed input with a very high compression ratio that produces a large output.
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Executive Summary

This vulnerability in pypdf prior to version 6.4.0 allows an attacker to craft a specially designed PDF that causes the library to use up to 1 GB of memory per content stream when parsing pages using the LZWDecode filter. This excessive memory usage can lead to performance degradation or denial of service. The issue has been fixed in version 6.4.0.

Impact Analysis

The vulnerability can cause your application or system using pypdf to consume excessive memory (up to 1 GB per stream) when processing maliciously crafted PDFs. This can lead to performance issues, crashes, or denial of service conditions, potentially disrupting normal operations.

Mitigation Strategies

Upgrade pypdf to version 6.4.0 or later, as this version contains the patch that fixes the vulnerability related to excessive memory usage when parsing PDFs with LZWDecode filters.

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