CVE-2025-66019

MEDIUM6.6

pypdf manipulated LZWDecode streams can exhaust RAM

Published Nov 25, 2025

Modified 1 months ago

Details

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.

References

WEB

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

WEB

https://github.com/py-pdf/pypdf/commit/96186725e5e6f237129a58a97cd19204a9ce40b2

WEB

https://github.com/py-pdf/pypdf/releases/tag/6.4.0

WEB

https://github.com/py-pdf/pypdf/security/advisories/GHSA-m449-cwjh-6pw7

ADVISORY

https://www.cve.org/CVERecord?id=CVE-2025-66019

CVSS Analysis