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CVE-2026-71870— pypdf: Possible large memory usage for large /ToUnicode 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.

py-pdf pypdf是py-pdf组织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 6.15.0之前版本存在资源管理错误漏洞，该漏洞源于pypdf/_cmap.py函数parse_bfrange在文本提取期间解析字体/ToUnicode CMap中异常大的source-code或destination-string tokens时，可能导致大量内存消耗。

CVSS 4.8 · Medium EPSS 0.18% · P7

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
py-pdf pypdf < 6.15.0 affected
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I. Basic Information for CVE-2026-71870

Vulnerability Information
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Vulnerability Title
pypdf: Possible large memory usage for large /ToUnicode streams
Source: CVE Program / CVE List V5
Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause large memory consumption when pypdf/_cmap.py function parse_bfrange parses unusually large source-code or destination-string tokens in a font /ToUnicode CMap during text extraction. This issue is fixed in 6.15.0.
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
未加控制的资源消耗(资源穷尽)
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 6.15.0之前版本存在资源管理错误漏洞，该漏洞源于pypdf/_cmap.py函数parse_bfrange在文本提取期间解析字体/ToUnicode CMap中异常大的source-code或destination-string tokens时，可能导致大量内存消耗。
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 < 6.15.0 -

II. Public POCs for CVE-2026-71870

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III. Intelligence Information for CVE-2026-71870

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Patches & Fixes for CVE-2026-71870 (2)

Vendor Advisories for CVE-2026-71870 (1)

Other References for CVE-2026-71870 (1)

IV. Related Vulnerabilities

Same product: pypdf
Same vendor: py-pdf
Same weakness: CWE-400

V. Comments for CVE-2026-71870

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