CVE-2026-59937
pypdf: Possible long runtimes for repeated malformed cross-reference entries
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.
INFO
Published Date :
July 8, 2026, 6:16 p.m.
Last Modified :
July 9, 2026, 8:39 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update pypdf to version 6.14.0.
- Apply patches for versions earlier than 6.14.0.
- Validate PDF file integrity before processing.
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-2026-59937.
| URL | Resource |
|---|---|
| https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae | Patch |
| https://github.com/py-pdf/pypdf/pull/3887 | Issue Tracking Patch |
| https://github.com/py-pdf/pypdf/releases/tag/6.14.0 | Product Release Notes |
| https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v | 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-2026-59937 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-2026-59937
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-2026-59937 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-59937 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]
Jul. 09, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/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) 6.14.0 Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae Types: Patch Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/pull/3887 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/releases/tag/6.14.0 Types: Product, Release Notes Added Reference Type GitHub, Inc.: https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v Types: Patch, Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jul. 09, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-59937', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-07-09T14:38:02.608932Z'} -
New CVE Received by [email protected]
Jul. 08, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'py-pdf', 'product': 'pypdf', 'versions': [{'status': 'affected', 'version': '< 6.14.0'}]}] Added Description pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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-400 Added Reference https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae Added Reference https://github.com/py-pdf/pypdf/pull/3887 Added Reference https://github.com/py-pdf/pypdf/releases/tag/6.14.0 Added Reference https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v