GitHub Advisoryadvisory · PyPI

GHSA-qpxp-75px-xjcp pypdf has inefficient decoding of array-based streams

MEDIUM Published 2026-03-18 Modified 2026-03-20 Official page ↗
Aliases
CVE-2026-33123
Ecosystem
PyPI
Packages
pypdf
Severity
Moderate
CVSS vector
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weaknesses
CWE-400, CWE-407
Reviewed
2026-03-18

Affected packages

• PyPI pypdf: < 6.9.1 → fixed in 6.9.1

Description

Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes and/or large memory usage. This requires accessing an array-based stream with lots of entries. Patches This has been fixed in pypdf==6.9.1. Workarounds If you cannot upgrade yet, consider applying the changes from PR #3686.

Related

Alias · CVE (1)

  • CVE-2026-33123 pypdf is a free and open-source pure-python PDF library. vulnerability

Weakness · CWE (2)

  • CWE-400 Uncontrolled Resource Consumption weakness
  • CWE-407 Inefficient Algorithmic Complexity weakness

References