| Package | Affected versions | Patched versions |
|---|---|---|
| pypdf | < 6.6.0 | 6.6.0 |
| pypdf | < 6.6.0 | 6.6.0 |
An attacker who exploits this vulnerability can craft a PDF which leads to possibly long runtimes for actually invalid files. This can be achieved by omitting the /Root entry in the trailer, while using a rather large /Size value. Only the non-strict reading mode is affected.
This has been fixed in pypdf==6.6.0.
from pypdf import PdfReader, PdfWriter
# Instead of
reader = PdfReader("file.pdf")
# use the strict mode:
reader = PdfReader("file.pdf", strict=True)
# Instead of
writer = PdfWriter(clone_from="file.pdf")
# use an explicit strict reader:
writer = PdfWriter(clone_from=PdfReader("file.pdf", strict=True))
This issue has been fixed in #3594.
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