pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

ImpactAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a call to readuntilwhitespace with an input which does not have whitespace for a long time. PatchesThis has been fixed in pypdf==6.15.0. WorkaroundsIf you cannot upgrade yet, consider applyin...