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CVE-2026-102995— pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)

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 是一个免费且开源的纯 Python PDF 处理库。在 6.18.1 版本之前，经过恶意构造的 PDF 文件可以在字体的 /ToUnicode 映射中放置异常大的源代码（source-code）或目标字符串（destination-string）令牌，导致 pypdf/_cmap.py 中的 parse_bfchar 函数在文本提取等操作过程中解码并保留这些超大值，从而消耗过量内存。该问题是此前针对 /ToUnicode 资源消耗漏洞修复工作的第二次后续跟进，仅涉及剩余的令牌长度处理路径。此问题已在 6

CVSS 8.7 · High
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I. Basic Information for CVE-2026-102995

Vulnerability Information
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Vulnerability Title
pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)
Source: CVE Program / CVE List V5
Vulnerability Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF can place unusually large source-code or destination-string tokens in a font /ToUnicode mapping, causing pypdf/_cmap.py parse_bfchar to decode and retain oversized values during operations such as text extraction and consume excessive memory. This is a second follow-up to earlier /ToUnicode resource-consumption fixes and is limited to the remaining token-length path. This issue is fixed in version 6.18.1.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/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

Affected Products

Vendor Product Affected Versions CPE Subscribe
py-pdf pypdf < 6.18.1 -

II. Public POCs for CVE-2026-102995

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III. Intelligence Information for CVE-2026-102995

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Other References for CVE-2026-102995 (4)

Same Patch Batch · py-pdf · 2026-09-30 · 8 CVEs total

CVE-2026-102998 8.7 HIGH pypdf: Possible long runtimes when generating appearance streams
CVE-2026-102997 8.7 HIGH pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
CVE-2026-102993 8.7 HIGH pypdf: Possible large memory usage when retrieving Roman page labels
CVE-2026-102994 8.7 HIGH pypdf: Possible long runtimes/large memory usage when parsing indirect objects
CVE-2026-102996 8.7 HIGH pypdf: Possible large memory usage when parsing font data
CVE-2026-102999 8.7 HIGH pypdf: Possible long runtimes with large amount of embedded files
CVE-2026-103000 8.7 HIGH pypdf: Possible large memory usage when retrieving alphabetical page labels

IV. Related Vulnerabilities

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

V. Comments for CVE-2026-102995

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