### Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires opening a file with large/wrong upper limits in the xref table.
### Patches
This has been fixed in [pypdf==6.21.2](https://github.com/py-pdf/pypdf/releases/tag/6.21.2).
### Workarounds
If you cannot upgrade yet, consider applying the changes from PR [#4239](https://github.com/py-pdf/pypdf/pull/4239).