CVE-2026-33123

MEDIUM

pypdf has inefficient decoding of array-based streams

Title source: cna
STIX 2.1

Description

pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.

References (3)

Scores

CVSS v3 6.5
EPSS 0.0001
EPSS Percentile 1.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-407 CWE-400
Status published
Products (3)
py-pdf/pypdf < 6.9.1
pypdf_project/pypdf < 6.9.1
pypi/pypdf 0 - 6.9.1PyPI
Published Mar 20, 2026
Tracked Since Mar 20, 2026