Infinite loop in PyPDF - CVE-2026-27628
Published: February 23, 2026
Vulnerability identifier: #VU123118
CSH Severity: Medium
CVSS v4: 6.9 [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]
CVE-ID: CVE-2026-27628
CWE-ID: CWE-835
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to infinite loop when loading circular /Prev entries in cross-reference streams. A remote attacker can trick a victim to open a specially crafted PDF and cause denial of service conditions.
Affected software
PyPDF
How to mitigate CVE-2026-27628
Install updates from vendor's website.
PyPDF - update to 6.7.2