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Status published
Medium
CVE-2025-66019
pypdf manipulated LZWDecode streams can exhaust RAM
Vulnerability Description
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.
Impact Analysis
Refer to official advisory for detailed impact metrics.
Remediation
Ensure systems are updated to the latest vendor-supplied patch levels.
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Credits & Attribution
No credits recorded in the NVD database.
References
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Affected Vendor
py-pdf
View all reports →Affected Software
pypdf
Vulnerable Versions:
< 6.4.0
Timeline
Official Publish:
November 25th, 2025
Last Modified:
January 20th, 2026
Added to House:
July 22nd, 2026