CUPS 2.3.3 is a general bug fix release, including:

CHANGES - 2.3.3 - 2020-04-24

Changes in CUPS v2.3.3

• CVE-2020-3898: The ppdOpen function did not handle invalid UI
  constraint. ppdcSource::get_resolution function did not handle
  invalid resolution strings.
• CVE-2019-8842: The ippReadIO function may under-read an extension

Changes in CUPS v2.3.2 (never tagged)

• Localization updates.