GHSA-hqmh-ppp3-xvm7

pypdf: manipulated stream length values can exhaust RAM

### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing a content stream with a rather large `/Length` value, regardless of the actual data length inside the stream. ### Patches This has been fixed in [pypdf==6.8.0](https://github.com/py-pdf/pypdf/releases/tag/6.8.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3675](https://github.com/py-pdf/pypdf/pull/3675). As far as we are aware, this mostly affects reading from buffers of unknown size, as returned by `open("file.pdf", mode="rb")` for example. Passing a file path or a `BytesIO` buffer to *pypdf* instead does not seem to trigger the vulnerability.