Infinite loop in PyPDF - CVE-2026-119205
Published: November 3, 2026
Vulnerability identifier: #VU158923
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-119205
CWE-ID: CWE-835
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to an unreachable loop exit condition in pypdf's DictionaryObject cloning functionality when processing a specially crafted PDF. A remote attacker can supply a crafted PDF that triggers an infinite loop when a DictionaryObject is cloned or duplicated to cause a denial of service.
Affected software
PyPDF
How to mitigate CVE-2026-119205
Install security update from vendor's website.
PyPDF - update to 6.21.4