Moderate severityNVD Advisory· Published Mar 20, 2026· Updated Mar 20, 2026
pypdf has inefficient decoding of array-based streams
CVE-2026-33123
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.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
pypdfPyPI | < 6.9.1 | 6.9.1 |
Affected products
1Patches
0No patches discovered yet.
Vulnerability mechanics
AI mechanics synthesis has not run for this CVE yet.
References
5- github.com/advisories/GHSA-qpxp-75px-xjcpghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-33123ghsaADVISORY
- github.com/py-pdf/pypdf/pull/3686ghsax_refsource_MISCWEB
- github.com/py-pdf/pypdf/releases/tag/6.9.1ghsax_refsource_MISCWEB
- github.com/py-pdf/pypdf/security/advisories/GHSA-qpxp-75px-xjcpghsax_refsource_CONFIRMWEB
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