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CVE-2026-84311— pypdf: Possible long runtimes/large memory usage when extracting XForm objects

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.

py-pdf pypdf是py-pdf组织开源的一款PDF文档处理组件。 pypdf 6.16.1之前版本存在资源管理错误漏洞，该漏洞源于攻击者可以制作恶意PDF，导致pypdf/_page.py中PageObject._extract_text和PageObject.extract_xform_text遍历复用表单XObject的有向无环图，产生指数级遍历路径，造成长时间运行和大量内存消耗。

CVSS 4.8 · Medium EPSS 0.14% · P3

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
py-pdf pypdf < 6.16.1 affected
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I. Basic Information for CVE-2026-84311

Vulnerability Information
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Vulnerability Title
pypdf: Possible long runtimes/large memory usage when extracting XForm objects
Source: CVE Program / CVE List V5
Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.1, an attacker can craft a PDF that causes pypdf/_page.py PageObject._extract_text and PageObject.extract_xform_text to traverse a directed acyclic graph of reused form XObjects in which each form invokes a child multiple times, creating exponentially many traversal paths and causing long runtimes and large memory consumption. This issue is fixed in version 6.16.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
过度迭代
Source: CVE Program / CVE List V5
Vulnerability Title
pypdf 资源管理错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
py-pdf pypdf是py-pdf组织开源的一款PDF文档处理组件。 pypdf 6.16.1之前版本存在资源管理错误漏洞，该漏洞源于攻击者可以制作恶意PDF，导致pypdf/_page.py中PageObject._extract_text和PageObject.extract_xform_text遍历复用表单XObject的有向无环图，产生指数级遍历路径，造成长时间运行和大量内存消耗。
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

Vendor Product Affected Versions CPE Subscribe
py-pdf pypdf < 6.16.1 -

II. Public POCs for CVE-2026-84311

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III. Intelligence Information for CVE-2026-84311

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Patches & Fixes for CVE-2026-84311 (2)

Vendor Advisories for CVE-2026-84311 (1)

Vendor Pages for CVE-2026-84311 (1)

Same Patch Batch · py-pdf · 2026-09-01 · 3 CVEs total

CVE-2026-84309 6.9 MEDIUM pypdf: Possible infinite loop for TreeObject.insert_child
CVE-2026-84310 4.8 MEDIUM pypdf: Possible long runtimes/large memory usage when retrieving outlines

IV. Related Vulnerabilities

Same product: pypdf
Same vendor: py-pdf
Same weakness: CWE-834

V. Comments for CVE-2026-84311

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