Infinite loop Affecting pypdf package, versions [,6.21.4)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-PYPDF-22132192
- published2 Nov 2026
- disclosed30 Oct 2026
- creditsmaeljaish771
Introduced: 30 Oct 2026
NewCVE-2026-119205 (opens in a new tab)How to fix?
Upgrade pypdf to version 6.21.4 or higher.
Overview
pypdf is an A pure-python PDF library capable of splitting, merging, cropping, and transforming PDF files
Affected versions of this package are vulnerable to Infinite loop via the _clone method in pypdf/generic/_data_structures.py when cloning a DictionaryObject that contains cyclic references. The loop-detection logic incorrectly checked the indirect reference of the newly generated clone object rather than the original source object, causing certain cycles to go undetected and resulting in an infinite loop that crashes the process.