Allocation of Resources Without Limits or Throttling in PyPDF - CVE-2026-31826
Published: April 27, 2026
Vulnerability identifier: #VU128011
CSH Severity: Medium
CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2026-31826
CWE-ID: CWE-770
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vendor: Pypdf Project
Affected software:
PyPDF
PyPDF
Detailed vulnerability description
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to allocation of resources without limits or throttling in the content stream parser when parsing a PDF content stream with a manipulated /Length value. A remote attacker can craft a PDF with a large /Length value to cause a denial of service.
This issue primarily affects cases where the library reads from buffers of unknown size, such as file objects opened in binary mode.
How to mitigate CVE-2026-31826
Install security update from vendor's website.