CVE-2026-22691
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.
Published:Jan 10, 2026
Last Modified:Apr 18, 2026
EPS:Jan 10, 2026
EPSS Score:0.00019
CVSS Score:5.3
Affected Products
Vendor
Product
Action
Vendor
Py-pdf
Product
Pypdf
Py-pdf
Pypdf
Vendor
Pypdf Project
Product
Pypdf
Pypdf Project
Pypdf
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
