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.
Published: 2026-03-20
Score: 5.1 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service via excessive memory/time consumption
Action: Immediate Patch
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-qpxp-75px-xjcp pypdf has inefficient decoding of array-based streams
History

Mon, 23 Mar 2026 16:00:00 +0000

Type Values Removed Values Added
First Time appeared Pypdf Project
Pypdf Project pypdf
CPEs cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:*
Vendors & Products Pypdf Project
Pypdf Project pypdf
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'}

cvssV3_1

{'score': 6.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H'}


Sat, 21 Mar 2026 05:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
References
Metrics threat_severity

None

cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L'}

threat_severity

Moderate


Fri, 20 Mar 2026 18:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 20 Mar 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Py-pdf
Py-pdf pypdf
Vendors & Products Py-pdf
Py-pdf pypdf

Fri, 20 Mar 2026 09:30:00 +0000

Type Values Removed Values Added
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.
Title pypdf has inefficient decoding of array-based streams
Weaknesses CWE-400
CWE-407
References
Metrics cvssV4_0

{'score': 5.1, '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'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-03-20T18:07:16.458Z

Reserved: 2026-03-17T20:35:49.926Z

Link: CVE-2026-33123

cve-icon Vulnrichment

Updated: 2026-03-20T16:04:05.465Z

cve-icon NVD

Status : Analyzed

Published: 2026-03-20T10:16:18.717

Modified: 2026-03-23T15:48:01.007

Link: CVE-2026-33123

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-20T09:09:12Z

Links: CVE-2026-33123 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-03-25T14:29:43Z

Weaknesses