pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.

Metrics

Attack Vector Network

Attack Complexity Low

Privileges Required None

Attack Requirements None

User Interaction None

Vulnerable System Confidentiality Impact None

Vulnerable System Integrity Impact None

Vulnerable System Availability Impact High

Subsequent System Confidentiality Impact None

Subsequent System Integrity Impact None

Subsequent System Availability Impact None

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Affected Vendors & Products

Vendors Products
Pypdf Project
  • Pypdf

No data.

No data.

References
Link Providers
https://github.com/py-pdf/pypdf/commit/96186725e5e6f237129a58a97cd19204a9ce40b2 cve-icon cve-icon cve-icon
https://github.com/py-pdf/pypdf/releases/tag/6.4.0 cve-icon cve-icon cve-icon
https://github.com/py-pdf/pypdf/security/advisories/GHSA-m449-cwjh-6pw7 cve-icon cve-icon cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-66019 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-66019 cve-icon
History

Wed, 03 Dec 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Moderate

Thu, 27 Nov 2025 10:00:00 +0000

Type Values Removed Values Added
First Time appeared Pypdf Project
Pypdf Project pypdf
Vendors & Products Pypdf Project
Pypdf Project pypdf

Wed, 26 Nov 2025 17:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 25 Nov 2025 23:45:00 +0000

Type Values Removed Values Added
Description pypdf is a free and open-source pure-python PDF library. Prior to version 6.4.0, an attacker who uses this vulnerability can craft a PDF which leads to a memory usage of up to 1 GB per stream. This requires parsing the content stream of a page using the LZWDecode filter. This issue has been patched in version 6.4.0.
Title pypdf manipulated LZWDecode streams can exhaust RAM
Weaknesses CWE-400
CWE-409
References
Metrics cvssV4_0

{'score': 6.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U'}
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2025-11-25T23:38:12.473Z

Updated: 2025-11-26T16:12:49.920Z

Reserved: 2025-11-21T01:08:02.613Z

Link: CVE-2025-66019

cve-icon Vulnrichment

Updated: 2025-11-26T16:12:46.019Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-11-26T00:15:51.263

Modified: 2025-12-01T15:39:53.100

Link: CVE-2025-66019

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-11-25T23:38:12Z

Links: CVE-2025-66019 - Bugzilla