Radicale before 1.1.2 and 2.x before 2.0.0rc2 is prone to timing oracles and simple brute-force attacks when using the htpasswd authentication method.
bugs.debian.org/861514
github.com/Kozea/Radicale/blob/1.1.2/NEWS.rst
github.com/Kozea/Radicale/commit/059ba8dec1f22ccbeab837e288b3833a099cee2d
github.com/Kozea/Radicale/commit/190b1dd795f0c552a4992445a231da760211183b
lists.debian.org/debian-lts-announce/2020/04/msg00019.html
nvd.nist.gov/vuln/detail/CVE-2017-8342
pypi.org/project/radicale