What is CVE-2026-33123?

CVE-2026-33123 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2026-03-20.

How severe is CVE-2026-33123?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Resource exhaustion in Py-Pdf Pypdf

CVE-2026-33123

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.

Vulnerability class: DoS (Denial of Service)

Published 2026-03-20 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.003 (28.6th percentile), scored 2026-09-23.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 28.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: 0.000

Affected products

Py-Pdf Pypdf — versions < 6.9.1
Pypdf Project

Weakness classification (CWE)

References

github.com/py-pdf/pypdf/security/advisories/GHSA-qpxp-75px-xjcp (Patch, Vendor Advisory)
github.com/py-pdf/pypdf/pull/3686 (Patch, Issue Tracking)
github.com/py-pdf/pypdf/releases/tag/6.9.1 (Product, Release Notes)

Frequently asked questions

What is CVE-2026-33123?: CVE-2026-33123 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Uncontrolled Resource Consumption. CVSS score: 6.5/10. Published 2026-03-20.
How severe is CVE-2026-33123?: Medium severity. CVSS v3 base score is 6.5 out of 10.