CVE-2026-22691
January 10, 2026
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.
Affected Packages
pypdf (CONDA):
Affected version(s) >=3.2.0 <6.6.0Fix Suggestion:
Update to version 6.6.0https://github.com/py-pdf/pypdf.git (GITHUB):
Affected version(s) >=v1.17 <6.6.0Fix Suggestion:
Update to version 6.6.0pypdf (PYTHON):
Affected version(s) >=1.0 <6.6.0Fix Suggestion:
Update to version 6.6.0pypdf (PYTHON):
Affected version(s) >=1.0 <6.6.0Fix Suggestion:
Update to version 6.6.0Related Resources (6)
Do you need more information?
Contact UsCVSS v4
Base Score:
2.7
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
NONE
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
NONE
Vulnerable System Availability
LOW
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
Exploit Maturity
UNREPORTED
CVSS v3
Base Score:
5.3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Weakness Type (CWE)
EPSS
Base Score:
0.02
