CVE-2026-33123— pypdf has inefficient decoding of array-based streams
Quick assessment
Affected
py-pdf pypdf
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
pypdf是py-pdf开源的一个免费开源的纯 python PDF 库。能够拆分、合并、裁剪和转换 PDF 文件的页面。 pypdf 6.9.1之前版本存在安全漏洞，该漏洞源于处理恶意PDF时存在缺陷，可能导致长时间运行或大量内存使用。
Possible ATT&CK Techniques 2 AI
T1059 · Command and Scripting Interpreter T1210 · Exploitation of Remote Services
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I. Basic Information for CVE-2026-33123
Vulnerability Information
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Vulnerability Title
pypdf has inefficient decoding of array-based streams
Source: CVE Program / CVE List V5
Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
未加控制的资源消耗(资源穷尽)
Source: CVE Program / CVE List V5
Vulnerability Title
pypdf 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
pypdf是py-pdf开源的一个免费开源的纯 python PDF 库。能够拆分、合并、裁剪和转换 PDF 文件的页面。 pypdf 6.9.1之前版本存在安全漏洞，该漏洞源于处理恶意PDF时存在缺陷，可能导致长时间运行或大量内存使用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)
Affected Products
II. Public POCs for CVE-2026-33123
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Patches & Fixes for CVE-2026-33123 (1)
Vendor Advisories for CVE-2026-33123 (1)
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Inefficient decoding of array-based streams · Advisory · py-pdf/pypdf · GitHub x_refsource_CONFIRM
Vendor Pages for CVE-2026-33123 (1)
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Release Version 6.9.1, 2026-03-17 · py-pdf/pypdf · GitHub x_refsource_MISC
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V. Comments for CVE-2026-33123
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