Impact

An attacker who uses this vulnerability can craft a PDF which leads to large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value.

Patches

This has been fixed in pypdf==6.13.3.

Workarounds

If you cannot upgrade yet, consider applying the changes from PR #3871.

Credits

• Thai Son Dinh from VinSOC Labs (R&D)