CVE-2026-102994pypdf is a free and open-source pure-python PDF library. Prior to 6.18.0, a crafted PDF containing indirect-object identifiers or generation-number tokens that continue for a long time without whitespace can cause pypdf/_reader.py and pypdf/generic/_base.py to scan excessive input through read_until_whitespace, resulting in long runtimes and application unavailability. This issue is fixed in version 6.18.0.