Resource exhaustion in PyPDF - #VU156728
Published: October 21, 2026
Vulnerability identifier: #VU156728
CSH Severity: Medium
CVSS v4: 6.9 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-400
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service through excessive PDF processing time.
The vulnerability exists due to uncontrolled resource consumption in pypdf's indirect object handling when processing repeated references to the same nonexistent object. A remote attacker can craft a PDF containing these references to cause prolonged processing when the affected portions of the file are loaded.
Affected software
PyPDF
Remediation
Install security update from vendor's website.
PyPDF - update to 6.21.2