Possible Infinite Loop when PdfWriter(clone_from) is used with a PDF
Date: 2023-10
Affected: pip/pypdf
Attack vector: other
Category: vulnerability-disclosure
Severity: Medium
CVE: CVE-2023-46250
CWE: CWE-835
CVSS: 5.1 (CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)

### Impact An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case when the pypdf-user manipulates an incoming malicious PDF e.g. by merging it with another PDF or by adding annotations. ### Patches The issue was fixed with #2264 ### Workarounds If you cannot update your version of pypdf, you should modify `pypdf/generic/_data_structures.py` just like #2264 did.


Mitigations:

Architectural layers (MAESTRO):