Infinite loop in PyPDF - CVE-2026-119203
Published: November 3, 2026
Vulnerability identifier: #VU158919
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-2026-119203
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 by triggering an infinite loop.
The vulnerability exists due to an unreachable loop exit condition in the pypdf standard cross-reference table parser when reaching the end of a file during a trailer search. A remote attacker can trick a victim into opening a crafted, incomplete PDF file without a trailer to cause the parser to loop indefinitely.
Affected software
PyPDF
How to mitigate CVE-2026-119203
Install security update from vendor's website.
PyPDF - update to 6.21.4