CVE-2026-33123 — Uncontrolled Resource Consumption in Pypdf

CWE-400 — Uncontrolled Resource ConsumptionCWE-407 — Inefficient Algorithmic ComplexityCWE-770 — Allocation of Resources Without Limits or Throttling7 documents6 sources
Severity
5.1MEDIUMNVD
EPSS
0.0%
top 98.24%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
4
Py-pdf PypdfPypdf Project PypdfDebian Pypdf+1 more
Timeline
PublishedMar 20

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.

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

Affected Packages6 packages

▶CVEListV5py-pdf/pypdf< 6.9.1
▶debiandebian/pypdf< pypdf 6.9.2-1 (forky)
▶debiandebian/pypdf2< pypdf 6.9.2-1 (forky)
▶NVDpypdf_project/pypdf< 6.9.1
▶PyPIpypdf_project/pypdf< 6.9.1

Patches

Patch: github.com ↗Patch: github.com ↗

🔴Vulnerability Details

3
OSV
CVE-2026-33123: pypdf is a free and open-source pure-python PDF library↗2026-03-20
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OSV
pypdf has inefficient decoding of array-based streams↗2026-03-18
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GHSA
pypdf has inefficient decoding of array-based streams↗2026-03-18
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📋Vendor Advisories

2
Red Hat
pypdf: pypdf: Denial of Service due to excessive resource consumption from crafted PDF↗2026-03-20
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Debian
CVE-2026-33123: pypdf - pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1...↗2026
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🕵️Threat Intelligence

1
Wiz
CVE-2026-33123 Impact, Exploitability, and Mitigation Steps | Wiz↗
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