CVE-2026-71852: CWE-834: Excessive Iteration in py-pdf pypdf
pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause long runtimes and large memory consumption when pypdf/_font.py function Font._collect_cid_character_widths expands unusually large CID font /W width ranges or excessive width entries during text extraction. This issue is fixed in 6.15.0.
AI Analysis
Technical Summary
The vulnerability in pypdf (CVE-2026-71852) arises from the Font._collect_cid_character_widths function expanding unusually large CID font /W width ranges or excessive width entries during text extraction. This leads to excessive iteration, resulting in long processing times and increased memory consumption. The flaw affects all versions prior to 6.15.0 and has been addressed in that release.
Potential Impact
An attacker can craft a malicious PDF that triggers excessive iteration in the font width collection logic, causing the pypdf library to consume excessive CPU and memory resources. This can degrade performance or potentially cause denial of service conditions in applications using vulnerable versions of pypdf for PDF text extraction.
Mitigation Recommendations
Upgrade to pypdf version 6.15.0 or later, where this issue is fixed. No other mitigations are specified or required.
CVE-2026-71852: CWE-834: Excessive Iteration in py-pdf pypdf
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.15.0, a crafted PDF can cause long runtimes and large memory consumption when pypdf/_font.py function Font._collect_cid_character_widths expands unusually large CID font /W width ranges or excessive width entries during text extraction. This issue is fixed in 6.15.0.
CVSS v4.0
Score 4.8medium
Affected software
py-pdf
pypdf
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability in pypdf (CVE-2026-71852) arises from the Font._collect_cid_character_widths function expanding unusually large CID font /W width ranges or excessive width entries during text extraction. This leads to excessive iteration, resulting in long processing times and increased memory consumption. The flaw affects all versions prior to 6.15.0 and has been addressed in that release.
Potential Impact
An attacker can craft a malicious PDF that triggers excessive iteration in the font width collection logic, causing the pypdf library to consume excessive CPU and memory resources. This can degrade performance or potentially cause denial of service conditions in applications using vulnerable versions of pypdf for PDF text extraction.
Mitigation Recommendations
Upgrade to pypdf version 6.15.0 or later, where this issue is fixed. No other mitigations are specified or required.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-08-07T18:26:53.523Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a772658bf8831d539846be1
Added to database: 08/08/2026, 12:51:36 UTC
Last enriched: 08/15/2026, 15:35:55 UTC
Last updated: 09/23/2026, 01:47:44 UTC
Views: 74
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