CVE-2026-54651
pypdf: Possible infinite loop when processing threads/articles in writer
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.13.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. This vulnerability is fixed in 6.13.1.
INFO
Published Date :
June 22, 2026, 9:16 p.m.
Last Modified :
June 24, 2026, 4:41 p.m.
Remotely Exploit :
No
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | MEDIUM | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update pypdf to version 6.13.1 or later.
- Apply security patches for the pypdf library.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-54651.
| URL | Resource |
|---|---|
| https://github.com/py-pdf/pypdf/pull/3839 | Issue Tracking |
| https://github.com/py-pdf/pypdf/releases/tag/6.13.1 | Patch |
| https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9xf-7f8q-9mcj | Mitigation Patch Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-54651 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-54651
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-54651 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-54651 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Jun. 24, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:pypdf_project:pypdf:*:*:*:*:*:*:*:* versions up to (excluding) 6.13.1 Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/pull/3839 Types: Issue Tracking Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/releases/tag/6.13.1 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9xf-7f8q-9mcj Types: Mitigation, Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 23, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-54651', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-23T12:09:57.316922Z'} -
New CVE Received by [email protected]
Jun. 22, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'py-pdf', 'product': 'pypdf', 'versions': [{'status': 'affected', 'version': '< 6.13.1'}]}] Added Description pypdf is a free and open-source pure-python PDF library. Prior to 6.13.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires merging a file with threads/articles into a writer. This vulnerability is fixed in 6.13.1. Added CVSS V4.0 AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-835 Added Reference https://github.com/py-pdf/pypdf/pull/3839 Added Reference https://github.com/py-pdf/pypdf/releases/tag/6.13.1 Added Reference https://github.com/py-pdf/pypdf/security/advisories/GHSA-g9xf-7f8q-9mcj