CVE-2025-66019

Summary

pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.

Affected Software

Weaknesses

• CWE-400: CWE-400: Uncontrolled Resource Consumption
• CWE-409: CWE-409: Improper Handling of Highly Compressed Data (Data Amplification)

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: yes
  • Technical Impact: partial

CVE Program Container

Additional References

• https://aydinnyunus.github.io/2025/12/20/cve-2025-66019-pypdf-lzw-dos/

References

• https://github.com/py-pdf/pypdf/security/advisories/GHSA-m449-cwjh-6pw7
• https://github.com/py-pdf/pypdf/commit/96186725e5e6f237129a58a97cd19204a9ce40b2
• https://github.com/py-pdf/pypdf/releases/tag/6.4.0

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