CVE-2025-62708: pypdf manipulated LZWDecode streams can exhaust RAM

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-10-22 · updated 2026-10-08
Weakness: CWE-409

Description

pypdf is a free and open-source pure-python PDF library. Prior to version 6.1.3, an attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the content stream of a page using the LZWDecode filter. This has been fixed in pypdf version 6.1.3.

Affected products

py-pdf pypdf: before 6.1.3 — fixed in 6.1.3

How to fix

Upgrade to a fixed version: py-pdf pypdf 6.1.3. Check the vendor advisory for mitigations.

References

https://github.com/py-pdf/pypdf/commit/e51d07807ffcdaf18077b9486dadb3dc05b368da
https://github.com/py-pdf/pypdf/pull/3502
https://github.com/py-pdf/pypdf/releases/tag/6.1.3
https://github.com/py-pdf/pypdf/security/advisories/GHSA-jfx9-29x2-rv3j

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