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.
CVE-2026-119208
CVSS base score
5.5 (v3.1)
Severity
MEDIUM
Attack vector
Local
Weakness
CWE-400
Last modified
November 2, 2026
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Affected products
py-pdf pypdf
References
- github.com Patch
- github.com Patch
- github.com Release Notes
- github.com Patch, Vendor Advisory