An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop if the PyPDF2 user wrote the following code:
from PyPDF2 import PdfFileReader, PdfFileWriter
from PyPDF2.pdf import ContentStream
reader = PdfFileReader("malicious.pdf", strict=False)
for page in reader.pages:
ContentStream(page.getContents(), reader)
PyPDF2==1.27.5
and later are patched.
Credits to Sebastian Krause for finding (issue) and fixing (PR) it.
github.com/py-pdf/PyPDF2
github.com/py-pdf/PyPDF2/issues/329
github.com/py-pdf/PyPDF2/pull/740
github.com/py-pdf/PyPDF2/releases/tag/1.27.5
github.com/py-pdf/PyPDF2/security/advisories/GHSA-xcjx-m2pj-8g79
github.com/pypa/advisory-database/tree/main/vulns/pypdf2/PYSEC-2022-194.yaml
lists.debian.org/debian-lts-announce/2022/06/msg00001.html
lists.debian.org/debian-lts-announce/2023/06/msg00013.html
nvd.nist.gov/vuln/detail/CVE-2022-24859