CVE-2026-22691 LOW

CVE-2026-22691: pypdf has possible long runtimes for malformed startxref

Vendor Py-Pdf
Product pypdf
Weakness CWE-1333
Published January 10, 2026
Last update January 12, 2026
View on NVD All CVEs

CVSS base score

2.7/10
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Confidentiality —
Integrity —

CVSS vector

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/E:U

What the vulnerability does

01Description

pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.

Key dates

02Disclosure timeline

January 10, 2026 CVE published
January 12, 2026 Record updated