Uncontrolled Memory Allocation in PyPDF - #VU126251
Published: April 15, 2026
Vulnerability identifier: #VU126251
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: N/A
CWE-ID: CWE-789
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 memory allocation with excessive size value in the FlateDecode stream processing logic when processing a PDF stream compressed using /FlateDecode with a /Predictor value other than 1 and large predictor parameters. A remote attacker can supply a specially crafted PDF to cause a denial of service.
Exploitation requires the application to access the crafted compressed stream.
Remediation
Install security update from vendor's website.