CVE-2026-119208: pypdf: Possible long runtimes/large memory usage for encrypted PDF files

Severity: high (CVSS 7.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-29 · updated 2026-10-30
Weakness: CWE-400

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive time and memory when an application accesses the page count of a crafted encrypted PDF whose page tree declares a forged /Count value. Even after successful decryption, page-count retrieval trusts the unvalidated declared count instead of walking the page tree, allowing the attacker-controlled value to drive excessive work and memory use. This issue is fixed in version 6.21.3.

Affected products

py-pdf pypdf: before 6.21.3

References

https://github.com/py-pdf/pypdf/commit/82b91951dc74496bb3efe6465434f041bb6a5e6b
https://github.com/py-pdf/pypdf/pull/4270
https://github.com/py-pdf/pypdf/releases/tag/6.21.3
https://github.com/py-pdf/pypdf/security/advisories/GHSA-62m5-6wh8-28x7

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