Description
pypdf is a free and open-source pure-python PDF library. An attacker who uses an infinite loop vulnerability that is present in versions prior to 6.6.2 can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. This has been fixed in pypdf 6.6.2. If projects cannot upgrade yet, consider applying the changes from PR #3610 manually.
Published: 2026-01-27
Score: 5.1 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Infinite loop causing denial of service through resource exhaustion
Action: 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-2q4j-m29v-hq73 pypdf has possible Infinite Loop when processing outlines/bookmarks
History

Wed, 25 Feb 2026 17:45:00 +0000

Type Values Removed Values Added
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

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'}


Fri, 06 Feb 2026 18:30:00 +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': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}


Thu, 29 Jan 2026 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


Wed, 28 Jan 2026 12:30:00 +0000

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

Tue, 27 Jan 2026 21:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

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


Tue, 27 Jan 2026 20:00:00 +0000

Type Values Removed Values Added
Description pypdf is a free and open-source pure-python PDF library. An attacker who uses an infinite loop vulnerability that is present in versions prior to 6.6.2 can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. This has been fixed in pypdf 6.6.2. If projects cannot upgrade yet, consider applying the changes from PR #3610 manually.
Title pypdf has possible Infinite Loop when processing outlines/bookmarks
Weaknesses CWE-835
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: 2026-01-27T20:51:48.030Z

Reserved: 2026-01-23T20:40:23.389Z

Link: CVE-2026-24688

cve-icon Vulnrichment

Updated: 2026-01-27T20:35:55.665Z

cve-icon NVD

Status : Analyzed

Published: 2026-01-27T20:16:24.193

Modified: 2026-02-25T17:40:23.320

Link: CVE-2026-24688

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-01-27T19:44:06Z

Links: CVE-2026-24688 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-04-18T02:00:10Z

Weaknesses