CVE-2026-113792: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') in py-pdf pypdf
Description
CVE-2026-113792 is a vulnerability in the pypdf library prior to version 6.20.1 where calling PdfWriter.find_outline_item on a specially crafted PDF with a cyclic outline hierarchy causes an infinite loop. This results in the process being blocked indefinitely. The issue has been fixed in version 6.20.1.
CVSS v4.0
Score 6.0medium
Affected software
py-pdf
pypdf
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The pypdf library, a pure-Python PDF processing tool, contains a loop with an unreachable exit condition (CWE-835) in the PdfWriter.find_outline_item function. When processing a crafted PDF that contains a cyclic outline hierarchy, the function can enter an infinite loop, causing the process to hang. This vulnerability affects all versions prior to 6.20.1 and was addressed by fixing the loop condition in version 6.20.1.
Potential Impact
An attacker can cause a denial of service by supplying a malicious PDF that triggers an infinite loop in the PdfWriter.find_outline_item function. This blocks the process handling the PDF, potentially leading to resource exhaustion or application unavailability. There is no indication of code execution or data leakage from this vulnerability.
Mitigation Recommendations
Upgrade to pypdf version 6.20.1 or later, where the infinite loop issue in PdfWriter.find_outline_item has been fixed. No other mitigation is necessary as the vendor has provided an official fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-10-20T17:39:41.373Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6ad8e5564d27ba8daac2408f
Added to database: 10/21/2026, 16:16:22 UTC
Last enriched: 10/21/2026, 16:30:30 UTC
Last updated: 10/21/2026, 17:15:44 UTC
Views: 3
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